The "Save Booking" messages that are received by BookingCenter have a check for overbookings built in. The check is only for properties who don't "auto assign" rooms to bookings in the set-up area of the System.

Therefore, if a Booking is to be saved to a Type only (i.e."Do not assign room is chosen"), there is a response we send back to the "SaveBooking" message:return ota_error($portid,$message,$version,$token,'', 6, 'Error: No Rooms Available', 0);

This response is ignored if the property is set to "Assign Rooms". For details on setting, go to How can I control if website bookings are automatically assigned a room?

Note: If the XML developer receives this error, attention needs to be taken. BookingCenter does not notify the property of the OVER-booking, so plan accordingly.

To cancel or modify a booking via the XML service, see this article.