I applied for my Change of status I539 from TD to F1 visa on Nov 14, few days back I checked the web site and found they sent me an RFE. When I applied initially after a month in December 20th I applied to withdraw my application (I539) but it appears that they never received my I539 withdrawal letter and they sent me the RFE in July. Now I just want to withdraw my I539, do I have to sent them the same withdrawal letter Again which I sent them initially in December