Any domestic fraternal benefit society may be converted and licensed as a mutual life insurance company by compliance with all the requirements of this act if the plan of conversion has been approved by the commissioner. A plan of conversion shall be prepared in writing by the board of directors setting forth in full the terms and conditions of conversion. The affirmative vote of two-thirds of all members of the supreme governing body at a regular or special meeting shall be necessary for the approval of such plan. No conversion shall take effect unless and until approved by the commissioner, who may give approval if the commissioner finds that the proposed change is in conformity with the requirements of law and not prejudicial to the certificate holders of the society.