So, I have an offer at School A and waitlisted at School B. If I don't get an offer from School B, School A is my top choice -- no question. However, if I do get an offer from School B, I prefer School B -- no question. The problem is that School A is saying that they might require me to accept or reject their offer by a certain time on April 15th. Suppose that I don't get anything from School B by that time, so I accept, but then School B sends me an offer later in the day.
Am I able to rescind my acceptance of to School A? What consequences would there be to backing out to go to School B?