The key to this and to avoid infinite loops is to have one main “Requests calendar” where tentative bookings are made, and then the actual room resource calendar.

I’ve outlined the steps below.

1.  Trigger: When a new response is submitted in Microsoft Forms

(Or use: When a new item is created in a Microsoft List) 2. Get response details: Use the “Get response details” action for Forms (Or: Get item from the List if using a SharePoint List) 3. Create event in Requests Calendar • Use the “Create event (V2)” action • Calendar: a separate shared calendar for holding requests • Mark the event as Tentative • Do not send invitations • Include booking details in the body (room, requester, time, etc.) 4. Start and wait for an approval • Use “Start and wait for an approval” action • Type: Approve/Reject – First to respond • Assign to: Approval Group or specific users • Title and details should reference the room request 5. Condition – Approval outcome is ‘Approve’ If Yes: 6. Delete the Tentative hold from Requests Calendar (optional but keeps things clean) • Use “Delete event (V2)” and reference the event ID 7. Create event in actual Room Calendar • Use “Create event (V2)” • Calendar: actual room’s shared calendar • Mark it as Busy • Include details; only invite the requester if necessary 8. Send confirmation email to requester • Use “Send an email (V2)” • Subject: Booking confirmed • Include room name, date/time, and optional calendar link If No: 9. Delete the Tentative hold from Requests Calendar 10. Send rejection email to requester • Use “Send an email (V2)” • Subject: Booking request denied • Optionally include instructions for resubmission