I heard that certain schools "lock" your admission after you get accepted and paid the deposit. That means that they make your information unaccessible to other schools through the Pharmcas. So if you get accepted later on, and school B sees that you are admitted to school A on the pharmcas, they might deny acceptance. So just for safety and as a courtesy for people on the waitlist, you should withdraw your acceptance if you are really sure that you are going to school B. Good luck! 🙂