Registration in composition scheme

first since the dealer hv turnover below threshold limit is not mandatory to get register under GST ACT.. once he voluntarily get registered himself then whole of the GST ACT levy on him... this means if in ur case assessee gets registered under composition scheme hv to file return under the act and pay tax accordingly... if you do not want surrender ur registration certificate file GSTR Form 16..

Assessee may withdraw registration providing reason of withdrawal as below turnover registration limit.

He may register when limit will cross

Yes agreed with above views...
Composition dealer can cancel the gst registration is below the threshold limit.

Agree with Abhay Sir...
Since your Aggregate Turnover is less than the threshold limit ( of ₹ 20 lakhs) , you are not required get registered under GST. You can cancel your Registration under Composition Scheme by filling GSTR Form 16 ...