Most theatres will allow past-dating, but only if there's seats to spare. (Which, by all accounts, SpongeBob has plenty to spare.) But typically shows will do it on weekday performances and you have to go in person. I'd do it soon though before spring break and easter travel revs up. But I think the Palace is a theatre with a public phone number, maybe you can call them?
"Hey little girls, look at all the men in shiny shirts and no wives!" - Jackie Hoffman, Xanadu, 19 Feb 2008