The securities commissioner may by order summarily postpone or suspend registration pending final determination of any proceeding under this section. Upon the entry of the order, the securities commissioner shall promptly notify the applicant or registrant, as well as the employer or prospective employer if the applicant or registrant is an agent or investment adviser representative, that it has been entered and of the reasons for the order and that within fifteen days after the receipt of a written request the matter will be set down for hearing. If no hearing is requested and none is ordered by the securities commissioner, the order remains in effect until it is modified or vacated by the securities commissioner. If a hearing is requested or ordered, the securities commissioner, after notice of and opportunity for hearing, may modify or vacate the order or extend it until final determination.