Go to Waltdisneyworld.com. In the upper right corner choose 'my disney vacation' then at the bottom of the list 'dining reservations'. You will then need to log in to your account. Enter your conf# & phone # then 'retrieve reservation'. Once it's brought up there is a button to cancel. Cick on it, it will ask you if you're sure, then choose yes. If you bring up the conf# it will come up w/big red letters saying 'cancelled'.