You can't add anything to a room only reservation. It will have to be changed to a package. You can buy the tickets separately from the room, but not the dining, so if you want the dining it must be changed to a package. That means you are in essence cancelling the room-only reservation and rebooking as a package. The above post is true - you must get someone on the phone who knows how to do this and retain your discount. The other consideration is that you will have to make a new depost (or pay in full if you are within 45 days) and you'll be refunded anything you have already paid on the room-only reservation. That payment will not transfer to the package.