27 C.F.R. § 771.69
At any time prior to the assignment of an administrative law judge, the licensee or permittee may, by filing written notice with the Director of Industry Operations, withdraw his request for a hearing. If such a notice is filed after assignment to the administrative law judge and prior to issuance of his recommended decision the Director of Industry Operations shall move the administrative law judge to dismiss the proceedings as moot. If such a notice is filed either after issuance of a notice of denial or notice of revocation and before assignment of the administrative law judge, or after issuance by the administrative law judge of his recommended decision and prior to the Director of Industry Operations' order disapproving the application or denying the renewal of or revoking the license or permit, the Director of Industry Operations shall, by order, dismiss the proceeding.
27 C.F.R. §771.69