Provisional GST registration requires PAN holders and may be cancelled if prescribed conditions are not complied with, pending final certificate. Section 139 mandates issuance of a provisional certificate of registration to persons already registered under existing laws who hold a valid Permanent Account Number, subject to prescribed form and conditions and liable to cancellation for non compliance; a final certificate is to be granted in prescribed form and conditions, and a provisional certificate is deemed never issued if registration is cancelled on the taxpayer's application that they were not liable to registration.