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I recently put down my tuition deposit at a school (hereinafter "School A") and last night I was admitted at my top choice school (hereinafter "School B"). I am sure this question has probably been answered here before but how do I go about withdrawing from School A? Do I just email admissions and withdraw and if so, how should I phrase it? Also, do I need notify School B that I had previously put down a deposit at School A or does School B not care?

In summation:

What do I need to do to transition from the first school I placed my deposit at to the new school I plan on attending?

I'd ask School B if it has a policy of refunding deposits put down at other schools while you waited on their decision.

Tell School A that you were admitted from the waitlist at your top-choice school and therefore you will need to withdraw, even though you were excited about attending. Something along those lines.