I've got another dumb question.....

....what happens if part of your party cannot make the trip and they are included on the initial ADR's....??? Can you remove them early and keep the ressie's, or do you lose them entirely and are forced to eat out of vending machines ??????? we are only 5 days out and the thought of popcorn and slim jims all week is sorta scary.....!!!! another thing is I'm not completely sure they are not coming, it's going to be a last second thing ???? any help or advice out there ???