If you need to cancel a reservation you need to contact the travel agent and you need to do this before the cancellation policy deadline. All GDS bookings need to be cancelled at the source, i.e. by the travel agent in their respective GDS (eg. Sabre, Amadeus, Gallileo).

In the case where the reservation is within the cancellation policy deadline, the travel agent is unlikely to be able to cancel the booking, and the hotel will still be charged a booking fee from SiteMinder because SiteMinder will still incur a charge.