many people have done it by mistake......right now no option is there .....but it is in talk that government is going to provide option in gst portal to go back to normal scheme who have mistakenly opted composition.....keep checking gst portal
you can do that.....by doing this you will be regular dealer with effect from the date when you file cmp-04......but if you want to be regular from 1st July itself, then you may have to wait for the decision of govt to allow such option ...