Cancellation Policies:
Room Only: Up to 6 days in advance no penalty, within 6 days 1 night penalty
Packages: 45 Days prior to arrival no penalty
44 Days or less $200 penalty
If you pay for a room only with a check then change to a package you WILL be able to transfer the payment from a room only to the package. If you pay with a credit card for the room only deposit you must wait for the refund.
As stated by a previous poster you are able to upgrade and add the dining plan and tickets up to 3 days in advance of your arrival date.