you cannot add DDP to a room only reservation. You would have to cancel that room only reservation, change it to a package, and buy tickets with it unless you have an AP or are eligible for the military room discount. Only those two types of guest can get the package without tickets. You would need to do that no later than 5 days before your arrival (6 if you booked online) because if you cancel a room only reservation after that, you lose your deposit. So before Feb. 26. If you rebook a package, you would need to pay for it in full when you do so. DVC members booking through member services can add a dining plan to their reservation anytime up to 2 days before arrival, no ticket purchase or reservation change needed. Appears the OP does not have a DVC reservation though.