If one has forgotten to fill out the JEE Mains form there is no way to sort out this problem bcoz JEE Mains is conducted by CBSE and we all know that CBSE rules are very strict and the thing on which they mainly focus is time management.My only suggestions to those who have forgotten to apply for JEE Mains due to some reasons, is that don't get upset always think positive and there are many good exams apart from JEE mains which you can give which are as follows:-1.VIT2.Manipal University3.NPAT4.MH-CET5.BITSAT6.SRMEtc.Thank You