Reschedule an existing Cal.com booking to a new start time via API v2, including seated bookings and events requiring email verification.

Documented steps

1. Authenticate with Authorization: 'Bearer <token>' (API key from Settings > Security, or a managed-user/OAuth token).
2. Confirm the booking is reschedulable: status must be 'accepted' or 'pending'. Bookings that are cancelled, rejected, or awaiting_host cannot be rescheduled and return 400.
3. Send POST https://api.cal.com/v2/bookings/{bookingUid}/reschedule.
4. Set the required header cal-api-version: 2026-02-25.
5. Include the required body field start as an ISO 8601 datetime for the new time.
6. Optionally include rescheduledBy (email of the initiator); if it matches the event owner's email, the rescheduled booking auto-confirms.
7. Optionally include reschedulingReason to explain the change.
8. If the event type has email verification enabled, include the required emailVerificationCode from the verification flow.
9. For a seated booking, include the required seatUid (UUID of the seat being moved).
10. Expect HTTP 201 with status 'success'; read data.start/data.end to confirm the new time and data.status to see whether it stayed pending or became accepted.
11. On a 400, GET /v2/bookings/{bookingUid} first — the booking is likely already cancelled, rejected, or an in-progress instant meeting.
12. Docs: https://cal.com/docs/api-reference/v2/bookings/reschedule-a-booking