Waitlisted? Here's what to do...

If you're waitlisted, first decide whether to remain on the list based on your level of interest and any conditions the college may have, such as limited housing or financial aid. If you choose to stay, reach out to the admissions office to understand your chances, express your continued enthusiasm in a letter, and update them on any new academic or extracurricular achievements. At the same time, secure a spot at another college by accepting an offer and submitting a deposit to ensure you have a backup plan.

https://bigfuture.collegeboard.org/plan-for-college/apply-to-college/after-youve-applied/what-to-do-if-youre-waitlisted