Withdraw then reapply?

I submitted Brown a few weeks ago. However, I wrote another version of one of the brown essays for another college that is way better than the one I submitted for brown. I was wondering if I am allowed to withdraw the brown app and put the new essay and reapply for the RD deadline? There were also some grammatical errors in my activities section for the brown app I submitted a few weeks ago, and I could correct those as well. Am I allowed to withdraw then reapply with new changes because the deadline isn’t for a few days.