OPT STEM Extension Application Withdrawal

Hello,I am recently applied for the OPT STEM Application and I have received a e-receipt with my case number. I realized that I have made some serious mistake in the form and would like to withdraw and re-apply again.My Question is :1) What is the process of withdrawal?2) How much time does it take to withdrawal the application?Any help is really appreciated!Thanks

Send a withdrawal letter to the same address that you sent application to with e-receipt number mentioned on the letter. A reason need not be mentioned. Send it by Fedex. This will result in your withdrawal letter being placed on top of your case file. It takes about 30 days for them to withdraw a filed document.