If a booking is imported from a channel and you have changed the room in Beds24 you need to change the setting for "Allow Channel Modifications" to prevent the channel to override the room change with the next update.
If the info codes BLOCKROOM LOCKROOM or BLOCKUNIT LOCKUNIT manual room changes by staff are not possible.
If you do not see these in the the drop down list you can manually add them in SETTINGS->ACCOUNT -> PREFERENCES "Booking Info Code Presets "