diff --git a/backend/src/app.ts b/backend/src/app.ts
index fc7a4a7..91f8af6 100644
--- a/backend/src/app.ts
+++ b/backend/src/app.ts
@@ -119,6 +119,7 @@ import {
   setWorkspaceSubscriptionStatusByStripeSubscriptionId,
   updateRescueVerificationStatus,
   updateWorkspace,
+  updateWorkspaceMemberRole,
   upsertWorkspaceMember,
 } from './repositories/workspaceRepository.js';
 import type {
@@ -3388,9 +3389,51 @@ app.post('/api/workspace/members', requireAuth, requireWriteAccess, requireWorks
   }
 });
 
+app.put('/api/workspace/members/:memberId', requireAuth, requireWriteAccess, requireWorkspaceRole(['owner', 'assistant']), async (req: Request, res: Response, next: NextFunction) => {
+  const parsed = z.object({ role: workspaceRoleSchema.exclude(['owner']) }).safeParse(req.body);
+
+  if (!parsed.success) {
+    res.status(400).json({ error: 'Invalid flock member role payload', details: parsed.error.flatten() });
+    return;
+  }
+
+  try {
+    const billingEmail = req.auth!.workspace.billing_email ? normalizeEmail(req.auth!.workspace.billing_email) : '';
+    const requesterIsBillingOwner = Boolean(billingEmail && billingEmail === normalizeEmail(req.auth!.user.email));
+    const member = await updateWorkspaceMemberRole({
+      memberId: req.params.memberId,
+      workspaceId: req.auth!.workspace.id,
+      role: parsed.data.role,
+      requesterMemberId: req.auth!.membership.id,
+      requesterIsBillingOwner,
+      requesterRole: req.auth!.membership.role,
+      billingEmail,
+    });
+
+    if (!member) {
+      res.status(404).json({ error: 'Flock member not found or cannot be changed.' });
+      return;
+    }
+
+    await writeAuditLog(req.auth!, 'workspace_member.role_updated', 'workspace_member', member.id, member.name, {
+      role: member.role,
+    });
+    res.json({ member: normalizeWorkspaceMember(member) });
+  } catch (error) {
+    next(error);
+  }
+});
+
 app.delete('/api/workspace/members/:memberId', requireAuth, requireWriteAccess, requireWorkspaceRole(['owner', 'assistant']), async (req: Request, res: Response, next: NextFunction) => {
   try {
-    const deleted = await deleteWorkspaceMember(req.params.memberId, req.auth!.workspace.id);
+    const billingEmail = req.auth!.workspace.billing_email ? normalizeEmail(req.auth!.workspace.billing_email) : '';
+    const requesterIsBillingOwner = Boolean(billingEmail && billingEmail === normalizeEmail(req.auth!.user.email));
+    const deleted = await deleteWorkspaceMember({
+      memberId: req.params.memberId,
+      workspaceId: req.auth!.workspace.id,
+      requesterMemberId: req.auth!.membership.id,
+      requesterIsBillingOwner,
+    });
 
     if (!deleted) {
       res.status(404).json({ error: 'Flock member not found or cannot be removed.' });
@@ -3398,7 +3441,6 @@ app.delete('/api/workspace/members/:memberId', requireAuth, requireWriteAccess,
     }
 
 	    await writeAuditLog(req.auth!, 'workspace_member.deleted', 'workspace_member', req.params.memberId);
-	    await writeAuditLog(req.auth!, 'integration_token.revoked', 'integration_token', req.params.tokenId);
 	    res.status(204).send();
   } catch (error) {
     next(error);
diff --git a/backend/src/repositories/workspaceRepository.test.ts b/backend/src/repositories/workspaceRepository.test.ts
index 2160bf1..fca4660 100644
--- a/backend/src/repositories/workspaceRepository.test.ts
+++ b/backend/src/repositories/workspaceRepository.test.ts
@@ -3,6 +3,7 @@ import test from 'node:test';
 
 import {
   createWorkspace,
+  deleteWorkspaceMember,
   deleteWorkspaceIfEmpty,
   ensureDefaultWorkspaceForUser,
   ensurePersonalWorkspaceForUser,
@@ -10,6 +11,7 @@ import {
   getPlatformAdminSummary,
   listOwnedWorkspacesByOwnerEmail,
   updateWorkspace,
+  updateWorkspaceMemberRole,
 } from './workspaceRepository.js';
 import { mockDb } from '../test/mockDb.js';
 import type { UserRow } from '../types.js';
@@ -259,6 +261,212 @@ test('listOwnedWorkspacesByOwnerEmail resolves accepted owner flocks by email',
   assert.match(calls[0].text, /workspaces\.id <> \$2/);
 });
 
+test('updateWorkspaceMemberRole changes a non-owner member role', async () => {
+  const { calls } = mockDb({
+    rowCount: 1,
+    rows: [
+      {
+        id: 'member-1',
+        workspace_id: 42,
+        user_id: 'user-2',
+        invite_email: 'helper@example.com',
+        name: 'Helper',
+        role: 'viewer',
+        accepted_at: '2026-04-14T00:00:00.000Z',
+        created_at: '2026-04-14T00:00:00.000Z',
+      },
+    ],
+  });
+
+  const member = await updateWorkspaceMemberRole({
+    memberId: 'member-1',
+    workspaceId: 42,
+    role: 'viewer',
+    requesterMemberId: 'owner-member',
+    requesterIsBillingOwner: false,
+    requesterRole: 'owner',
+    billingEmail: 'billing@example.com',
+  });
+
+  assert.equal(member?.role, 'viewer');
+  assert.deepEqual(calls[0].params, ['member-1', 42, 'viewer', false, 'owner-member', 'billing@example.com', 'owner']);
+  assert.match(calls[0].text, /UPDATE workspace_members/);
+  assert.match(calls[0].text, /role <> 'owner'/);
+});
+
+test('updateWorkspaceMemberRole returns null when no non-owner member matches', async () => {
+  mockDb({
+    rowCount: 0,
+    rows: [],
+  });
+
+  const member = await updateWorkspaceMemberRole({
+    memberId: 'owner-member',
+    workspaceId: 42,
+    role: 'viewer',
+    requesterMemberId: 'owner-member',
+    requesterIsBillingOwner: false,
+    requesterRole: 'owner',
+    billingEmail: 'billing@example.com',
+  });
+
+  assert.equal(member, null);
+});
+
+test('updateWorkspaceMemberRole lets the billing owner change another owner role', async () => {
+  const { calls } = mockDb({
+    rowCount: 1,
+    rows: [
+      {
+        id: 'other-owner',
+        workspace_id: 42,
+        user_id: 'user-2',
+        invite_email: 'other@example.com',
+        name: 'Other Owner',
+        role: 'assistant',
+        accepted_at: '2026-04-14T00:00:00.000Z',
+        created_at: '2026-04-14T00:00:00.000Z',
+      },
+    ],
+  });
+
+  const member = await updateWorkspaceMemberRole({
+    memberId: 'other-owner',
+    workspaceId: 42,
+    role: 'assistant',
+    requesterMemberId: 'billing-owner',
+    requesterIsBillingOwner: true,
+    requesterRole: 'owner',
+    billingEmail: 'billing@example.com',
+  });
+
+  assert.equal(member?.role, 'assistant');
+  assert.deepEqual(calls[0].params, ['other-owner', 42, 'assistant', true, 'billing-owner', 'billing@example.com', 'owner']);
+  assert.match(calls[0].text, /id <> \$5/);
+});
+
+test('updateWorkspaceMemberRole does not let the billing owner change their own owner role', async () => {
+  mockDb({
+    rowCount: 0,
+    rows: [],
+  });
+
+  const member = await updateWorkspaceMemberRole({
+    memberId: 'billing-owner',
+    workspaceId: 42,
+    role: 'assistant',
+    requesterMemberId: 'billing-owner',
+    requesterIsBillingOwner: true,
+    requesterRole: 'owner',
+    billingEmail: 'billing@example.com',
+  });
+
+  assert.equal(member, null);
+});
+
+test('updateWorkspaceMemberRole lets a non-billing owner change another non-billing owner role', async () => {
+  const { calls } = mockDb({
+    rowCount: 1,
+    rows: [
+      {
+        id: 'other-owner',
+        workspace_id: 42,
+        user_id: 'user-2',
+        invite_email: 'other@example.com',
+        name: 'Other Owner',
+        role: 'assistant',
+        accepted_at: '2026-04-14T00:00:00.000Z',
+        created_at: '2026-04-14T00:00:00.000Z',
+      },
+    ],
+  });
+
+  const member = await updateWorkspaceMemberRole({
+    memberId: 'other-owner',
+    workspaceId: 42,
+    role: 'assistant',
+    requesterMemberId: 'non-billing-owner',
+    requesterIsBillingOwner: false,
+    requesterRole: 'owner',
+    billingEmail: 'billing@example.com',
+  });
+
+  assert.equal(member?.role, 'assistant');
+  assert.deepEqual(calls[0].params, ['other-owner', 42, 'assistant', false, 'non-billing-owner', 'billing@example.com', 'owner']);
+  assert.match(calls[0].text, /LOWER\(BTRIM\(COALESCE\(invite_email, email\)\)\) <> LOWER\(BTRIM\(\$6\)\)/);
+});
+
+test('updateWorkspaceMemberRole does not let a non-billing owner change the billing owner role', async () => {
+  mockDb({
+    rowCount: 0,
+    rows: [],
+  });
+
+  const member = await updateWorkspaceMemberRole({
+    memberId: 'billing-owner',
+    workspaceId: 42,
+    role: 'assistant',
+    requesterMemberId: 'non-billing-owner',
+    requesterIsBillingOwner: false,
+    requesterRole: 'owner',
+    billingEmail: 'billing@example.com',
+  });
+
+  assert.equal(member, null);
+});
+
+test('deleteWorkspaceMember removes non-owner members without billing owner access', async () => {
+  const { calls } = mockDb({
+    rowCount: 1,
+    rows: [{ id: 'member-1' }],
+  });
+
+  const deleted = await deleteWorkspaceMember({
+    memberId: 'member-1',
+    workspaceId: 42,
+    requesterMemberId: 'owner-member',
+    requesterIsBillingOwner: false,
+  });
+
+  assert.equal(deleted, true);
+  assert.deepEqual(calls[0].params, ['member-1', 42, false, 'owner-member']);
+  assert.match(calls[0].text, /role <> 'owner'/);
+});
+
+test('deleteWorkspaceMember lets the billing owner remove another owner', async () => {
+  const { calls } = mockDb({
+    rowCount: 1,
+    rows: [{ id: 'other-owner' }],
+  });
+
+  const deleted = await deleteWorkspaceMember({
+    memberId: 'other-owner',
+    workspaceId: 42,
+    requesterMemberId: 'billing-owner',
+    requesterIsBillingOwner: true,
+  });
+
+  assert.equal(deleted, true);
+  assert.deepEqual(calls[0].params, ['other-owner', 42, true, 'billing-owner']);
+  assert.match(calls[0].text, /id <> \$4/);
+});
+
+test('deleteWorkspaceMember does not let the billing owner remove their own owner membership', async () => {
+  mockDb({
+    rowCount: 0,
+    rows: [],
+  });
+
+  const deleted = await deleteWorkspaceMember({
+    memberId: 'billing-owner',
+    workspaceId: 42,
+    requesterMemberId: 'billing-owner',
+    requesterIsBillingOwner: true,
+  });
+
+  assert.equal(deleted, false);
+});
+
 test('getPlatformAdminSummary counts memorialized birds separately', async () => {
   const { calls } = mockDb({
     rowCount: 1,
diff --git a/backend/src/repositories/workspaceRepository.ts b/backend/src/repositories/workspaceRepository.ts
index 44d9171..565bcbd 100644
--- a/backend/src/repositories/workspaceRepository.ts
+++ b/backend/src/repositories/workspaceRepository.ts
@@ -364,19 +364,77 @@ export const upsertWorkspaceMember = async ({
   return result.rows[0] ?? null;
 };
 
-export const deleteWorkspaceMember = async (memberId: string, workspaceId: number) => {
+export const deleteWorkspaceMember = async ({
+  memberId,
+  workspaceId,
+  requesterMemberId,
+  requesterIsBillingOwner,
+}: {
+  memberId: string;
+  workspaceId: number;
+  requesterMemberId: string;
+  requesterIsBillingOwner: boolean;
+}) => {
   const result = await db.query<{ id: string }>(
     `DELETE FROM workspace_members
      WHERE id = $1
        AND workspace_id = $2
-       AND role <> 'owner'
+       AND (
+         role <> 'owner'
+         OR (
+           $3 = TRUE
+           AND id <> $4
+         )
+       )
      RETURNING id`,
-    [memberId, workspaceId],
+    [memberId, workspaceId, requesterIsBillingOwner, requesterMemberId],
   );
 
   return Boolean(result.rowCount);
 };
 
+export const updateWorkspaceMemberRole = async ({
+  memberId,
+  workspaceId,
+  role,
+  requesterMemberId,
+  requesterIsBillingOwner,
+  requesterRole,
+  billingEmail,
+}: {
+  memberId: string;
+  workspaceId: number;
+  role: WorkspaceMemberRow['role'];
+  requesterMemberId: string;
+  requesterIsBillingOwner: boolean;
+  requesterRole: WorkspaceMemberRow['role'];
+  billingEmail: string;
+}) => {
+  const result = await db.query<WorkspaceMemberRow>(
+    `UPDATE workspace_members
+     SET role = $3
+     WHERE id = $1
+       AND workspace_id = $2
+       AND (
+         role <> 'owner'
+         OR (
+           id <> $5
+           AND (
+             $4 = TRUE
+             OR (
+               $7 = 'owner'
+               AND LOWER(BTRIM(COALESCE(invite_email, email))) <> LOWER(BTRIM($6))
+             )
+           )
+         )
+       )
+     RETURNING id, workspace_id, user_id, COALESCE(invite_email, email) AS invite_email, name, role, accepted_at::text, created_at`,
+    [memberId, workspaceId, role, requesterIsBillingOwner, requesterMemberId, billingEmail, requesterRole],
+  );
+
+  return result.rows[0] ?? null;
+};
+
 export const listRescueWorkspacesForAdmin = async () => {
   const result = await db.query<
     WorkspaceRow & {
diff --git a/frontend/src/App.tsx b/frontend/src/App.tsx
index 8774d28..d0ef1b0 100644
--- a/frontend/src/App.tsx
+++ b/frontend/src/App.tsx
@@ -1676,6 +1676,7 @@ function App() {
   const [editingMedicationId, setEditingMedicationId] = useState('');
   const [deletingMedicationId, setDeletingMedicationId] = useState('');
   const [savingMedicationAdministrationId, setSavingMedicationAdministrationId] = useState('');
+  const [updatingWorkspaceMemberId, setUpdatingWorkspaceMemberId] = useState('');
   const [removingWorkspaceMemberId, setRemovingWorkspaceMemberId] = useState('');
   const [expandedSettingsSection, setExpandedSettingsSection] = useState<SettingsSection | null>(null);
 
@@ -1683,6 +1684,11 @@ function App() {
     () => birds.find((bird) => bird.id === selectedBirdId) ?? null,
     [birds, selectedBirdId],
   );
+  const isBillingOwner = Boolean(
+    authSession?.user.email &&
+      workspace?.billingEmail &&
+      authSession.user.email.trim().toLowerCase() === workspace.billingEmail.trim().toLowerCase(),
+  );
   const selectedBirdAdoptionTransferCode = selectedBird ? adoptionTransferCodes[selectedBird.id] ?? '' : '';
 	  const editingBird = useMemo(
 	    () => birds.find((bird) => bird.id === editingBirdId) ?? null,
@@ -4986,7 +4992,15 @@ function App() {
         email: data.member.inviteEmail,
       };
 
-      setWorkspaceMembers((current) => [...current, nextMember]);
+      setWorkspaceMembers((current) => {
+        const existingIndex = current.findIndex((member) => member.id === nextMember.id);
+
+        if (existingIndex === -1) {
+          return [...current, nextMember];
+        }
+
+        return current.map((member) => (member.id === nextMember.id ? nextMember : member));
+      });
       setWorkspaceMemberForm(emptyWorkspaceMemberForm);
     } catch (memberError) {
       setError(memberError instanceof Error ? memberError.message : 'Unable to add rescue team member.');
@@ -4995,6 +5009,40 @@ function App() {
     }
   };
 
+  const handleUpdateWorkspaceMemberRole = async (memberId: string, role: WorkspaceRole) => {
+    setError('');
+    setUpdatingWorkspaceMemberId(memberId);
+
+    try {
+      const response = await apiFetch(`/workspace/members/${memberId}`, authToken, {
+        method: 'PUT',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({ role }),
+      });
+
+      if (!response.ok) {
+        throw new Error(await readErrorMessage(response, 'Unable to update collaborator role.'));
+      }
+
+      const data = (await readJsonSafely<{ member?: WorkspaceMember }>(response)) ?? {};
+
+      if (!data.member) {
+        throw new Error('Unable to update collaborator role.');
+      }
+
+      const updatedMember = {
+        ...data.member,
+        email: data.member.inviteEmail,
+      };
+
+      setWorkspaceMembers((current) => current.map((member) => (member.id === memberId ? updatedMember : member)));
+    } catch (memberError) {
+      setError(memberError instanceof Error ? memberError.message : 'Unable to update collaborator role.');
+    } finally {
+      setUpdatingWorkspaceMemberId('');
+    }
+  };
+
   const handleRemoveWorkspaceMember = async (memberId: string) => {
     setError('');
     setRemovingWorkspaceMemberId(memberId);
@@ -7877,7 +7925,6 @@ function App() {
                         })
                       }
                     >
-                      <option value="owner">Owner</option>
                       <option value="assistant">Assistant</option>
                       <option value="caregiver">Caregiver</option>
                       <option value="viewer">Viewer</option>
@@ -7890,23 +7937,63 @@ function App() {
 
                 <div className="recent-list">
                   {workspaceMembers.length ? (
-                    workspaceMembers.map((member) => (
-                      <article key={member.id} className="vet-visit-card">
-                        <strong>{member.name}</strong>
-                        <span>
-                          {formatWorkspaceRole(member.role)} • {member.email || member.inviteEmail}
-                        </span>
-                        <small>{member.acceptedAt ? 'Active access' : 'Invitation pending'}</small>
-                        <button
-                          className="secondary-button"
-                          onClick={() => handleRemoveWorkspaceMember(member.id)}
-                          type="button"
-                          disabled={removingWorkspaceMemberId === member.id || member.role === 'owner'}
-                        >
-                          {member.role === 'owner' ? 'Owner' : removingWorkspaceMemberId === member.id ? 'Removing...' : 'Remove'}
-                        </button>
-                      </article>
-                    ))
+                    workspaceMembers.map((member) => {
+                      const memberEmail = member.email || member.inviteEmail || '';
+                      const memberIsBillingOwner = Boolean(
+                        workspace?.billingEmail &&
+                          memberEmail.trim().toLowerCase() === workspace.billingEmail.trim().toLowerCase(),
+                      );
+                      const canRemoveOwner = member.role === 'owner' && isBillingOwner && member.id !== activeMembership?.id;
+                      const canChangeOwnerRole =
+                        member.role === 'owner' &&
+                        activeMembership?.role === 'owner' &&
+                        member.id !== activeMembership.id &&
+                        (isBillingOwner || !memberIsBillingOwner);
+                      const canRemoveMember = member.role !== 'owner' || canRemoveOwner;
+
+                      return (
+                        <article key={member.id} className="vet-visit-card">
+                          <strong>{member.name}</strong>
+                          <span>
+                            {formatWorkspaceRole(member.role)} • {member.email || member.inviteEmail}
+                          </span>
+                          <small>{member.acceptedAt ? 'Active access' : 'Invitation pending'}</small>
+                          <label>
+                            Role
+                            <select
+                              value={member.role}
+                              onChange={(event) => handleUpdateWorkspaceMemberRole(member.id, event.target.value as WorkspaceRole)}
+                              disabled={
+                                (member.role === 'owner' && !canChangeOwnerRole) ||
+                                updatingWorkspaceMemberId === member.id ||
+                                removingWorkspaceMemberId === member.id
+                              }
+                            >
+                              {member.role === 'owner' ? <option value="owner">Owner</option> : null}
+                              <option value="assistant">Assistant</option>
+                              <option value="caregiver">Caregiver</option>
+                              <option value="viewer">Viewer</option>
+                            </select>
+                          </label>
+                          <button
+                            className="danger-button"
+                            onClick={() => handleRemoveWorkspaceMember(member.id)}
+                            type="button"
+                            disabled={
+                              removingWorkspaceMemberId === member.id ||
+                              updatingWorkspaceMemberId === member.id ||
+                              !canRemoveMember
+                            }
+                          >
+                            {removingWorkspaceMemberId === member.id
+                              ? 'Removing...'
+                              : canRemoveMember
+                                ? 'Remove access'
+                                : 'Owner'}
+                          </button>
+                        </article>
+                      );
+                    })
                   ) : (
                     <article className="vet-visit-card empty-card">
                       <strong>No collaborators yet</strong>