It more depends on what restaurant it is. If you had to put a credit card down, then I was told by the dining CM that you would have to pay $10 for each person that didn't show up. I don't know how stricit they are with this policy. If you didn't put a CC down then I don't really think its that big of a deal. It is really easy to change though. Just call the 1800 dining number and have them change the ressie from 13 to 12.