How to make an online application for Gst Cmp - 4

if you get answer then pls pls inform me too. i raised 18% tax invoice of july and aug-17 .when i login for GST-3B at that time i know that my registration is bymistakly in comosition scheme.so please help me out

the GSTN portal has not  made this function operational till date. one of my client has wrongly opted in for composition, but cannt come out resently, even though rules mention form CMP 4 for the purpose. it is a big mitake in the GST portal. needs to be removed.