If you reserved a Bounceback reservation and once your home you decide to change resorts or your room category that can be done, as long as it falls within the listed dates that was printed on the Bounceback sheet which was in your room.
Obviously the only thing you can't do is make a brand new Bounceback reservation since that can only be done when your currently staying at a Walt Disney World Resort.
As for the cancellation policy it's still the same like it would be for any room only reservation, which needs to be done 72 hours before you arrive so you can get your money back.