Room changes can be done in 3 ways:
1. By drag n'drop in the Grid. You can switch room, upgrade, extend or shorten stay. Rate will always change to current BAR (If reservation is booked with a code the rate will also apply the code). Read more here.
2. 'Switch Room' function in Reservation view where you can only switch room and upgrade, rate will never change. Read more here.
3. 'Date and or Room Change' in Reservation view where you can switch room, upgrade, extend or shorten stay, you will be given options on what rate the room should get after the change. Read more here.