If someone deletes a Type, you can still bring it back. Look under Rooms for the codes of previous Types and then go to Types and click ADD and re-enter the Type ID exactly.
However, you will now note that the Rooms will show on the Tape Chart but the Room function that drives the 'Choose Room' on the New Booking and the Room Assignment pages will NOT 'see' the rooms. To get the Rooms to be linked properly again, do ONE of these options:
1) Go to each Room, click EDIT and then SAVE and the Room to Type link gets re-stored again.
2) ask a DB admin (i.e., a BookingCenter Support rep) to set the "Offline" flag for all those rooms to 'NO".