Hi, this is my problem too.
I have not yet recieved my I20 form though, and do not have full fund yet so more likely to differ for other semesters.

Please let me know how long I will be permitted to postpone initiation of my studies and to whom actually I must apply for this?
May I differ for the other Fall semester to acquire full financial assisstantship position?

thanks you all beforehnad for your caring responses.