When your Calendly iframe integration misses reschedules, stop looking for a reschedule message event, there isnt one. Subscribe to Calendly webhooks: a reschedule arrives as a cancelled event plus a created event. Match them by invitee or event details on your side to record it as a reschedule rather than a cancel plus a new booking.

Context: Stack Overflow #69102073 (accepted answer, 5 votes): the asker captured the calendly.event_scheduled message from the embedded iframe but found no equivalent event fires on reschedule. The accepted answer confirms there is no official reschedule listener: when a reschedule happens, Calendly fires the cancelled and created webhook events instead.