call both schools (the one you rejected and the waitlist) and see what they have to say

Waitlist movement at this point is unlikely, but call the school you turned down, explain that you think you made a mistake, and see if they might have space and take your child. It's a long shot, but you might as well ask- maybe you'll get lucky.

Is there any hope for getting off the waitlist at this late stage? Regretting the spot we took at TJ and wish we had accepted an offer at a slightly less rigorous but more well rounded private. Still on the waitlist at another school and want to know if there is any late stage movement.