I'm allowed to send Gmail Schemas of "EventReservation" type (with "reservationStatus" = "http://schema.org/Confirmed"), and they're inserting themselves automatically to Google Calendar as expected, but there's no way I can cancel one of those events.
I've tried changing the "reservationStatus" parameter to "https://schema.org/Cancelled" and "https://schema.org/ReservationCancelled" (as mentioned in schema.org) but it didn't work.
I read here that Google removed that feature on Dec. '19, but again there was a publication on Google Developer on Mar '20 that says that they enabled event cancellation in schemas (not specifically in Gmail), but those tips didn't work either.
Both JSON+LD structures are the same except for the keys mentioned above.