i'm an international student applying for a PhD program in the US. I've received an offer for financial aid from University X which I have to respond to by April 22. however i have yet to receive responses from 3 schools which are higher in my preference list. So i called one of them up and they said that it is not in their hands but in the hands of the graduate committee regarding when the decision can be made available. What should I do in this situation? If i accept the offer from X say on the 22nd (in case I would not have received a reply from the other univs by that date), and I do get an offer from one of those schools later on, could I reject the offer from X at that time? what are the repercussions of rejecting said offer?