Reapplying

You can always reapply; however, when you are resubmitting, make sure you have learned from critiques you got on the first time.

However, you can count on only 1-2 resubmissionss: the idea is not that you submit a bad proposal, get feedback, correct, resubmit, correct again, and so forth. The plan has to be yours, show your abilities; the university won't coach you until it finds your application good. It lurks a conflict of interest here.