You should be careful when changing the room category for guests that have made bookings through OTA's.  

If you have to change the room category, this should be done through the OTA's to make sure the databases are similar.

If you switch the room category only locally and e.g. needs to make changes to the booking (add a comment or change name), the system will become confused and will delete the old booking and attempt to book a room that is already rented, and you will get encounter something similar to this:

Contact information:

Phone: +47 33 20 08 08
System provided by GetShop AS -