According to
https://www.aamc.org/students/applying/amcas/153900/aamc_recommendations_for_applicants.html :
In fairness to other applicants, when an applicant has made a decision, prior to May 15, April 30 for MD-PhD applicants, not to attend a medical school or program that has made an offer of acceptance, the applicant promptly withdraw his or her application from that (those) other school(s) or program(s) by written correspondence delivered by regular or electronic methods.
By May 15 of the matriculation year (April 15 for schools whose first day of class is on or before July 30), April 30 for MD-PhD programs, each applicant who has received an offer of acceptance from more than one school or program choose the specific school or program at which the applicant prefers to enroll and withdraw his or her application, by written correspondence delivered by regular or electronic methods, from all other schools or programs from which acceptance offers have been received.
Immediately upon enrollment in, or initiation of an orientation program immediately prior to enrollment at, a U.S. or Canadian school or program, each applicant withdraw his or her application from consideration at all other schools or programs at which he or she remains under consideration.
Anyone know what we have to do if we get another acceptance between April 15 and enrollment? I know a lot of us are still on the UF hold list and expecting to hear a decision in "mid-April."