I just spent two days attempting to cancel a single invitee via an HTTP request and FINALLY got it to work! I just want to make a post so that others know it’s possible. There is another post that now makes sense because it is similar to what they explained.

I was creating a make automation so that if a user isn’t paying the subscription it auto cancels the event but only for the single invitee and not cancelling the entire event for everyone. 

HTTP make a request module

PUT https://calendly.com/api/booking/cancellations/UUID

UUID (CUSTOM VARIABLE NAME) = cancellation url - the https://calendly.com/cancellations so just the /string of numbers&letters 

RAW body type

Content type = JSON(application/json)

Request content = { "cancel_reason": "WHATEVER REASON" }