From the 2010 Marathon package site:
Cancellation of Reservation - If the reservation is cancelled amounts paid, minus cancellation fees, vacation insurance premium, and other amounts owed, will be refunded. For a cancellation made 44 to 6 days prior to guest arrival, there is a cancellation fee of $100 per package, plus any cancellation fees assessed by third party hotels or other suppliers.
For a cancellation made 5 days or less prior to guest arrival, there is a cancellation fee of $200 per package, plus any cancellation fees assessed by third party hotels or other suppliers. No refunds are given for cancellation of a Grand Gathering experience made 5 days or less prior to the experience date.
Guest will be responsible for any cancellation fees assessed by an airline. In the case of a non-refundable airline ticket, the cancellation fee is equal to the entire ticket price. Cancellation of a refundable airline ticket must be made at least 24 hours prior to the scheduled airline departure time.
Vacation insurance is nonrefundable. Upon any cancellation, the charge for vacation insurance will be added to the other applicable cancellation fees.
Changes to Reservation - For a change made 44 days or less prior to guest arrival that results in a change in the package price, a change fee of $50 per package, plus any change fees assessed by hotels or other suppliers, will be charged. Disney reserves the right to restrict changes to any reservation. Such change fees must be paid in addition to any increase in the package price resulting from the change. If air travel has been ticketed, guest will be responsible for any increase in airfare as well as the change fee assessed by the airline.
