Any domestic society may be converted and licensed as a mutual life insurance company by compliance with all the requirements of the insurance laws of this state for mutual life insurance companies. A plan of conversion must 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 is necessary for the approval of the conversion plan. No conversion may take effect until approved by the commissioner who may approve the conversion if the commissioner finds that the proposed change conforms to the requirements of law and is not prejudicial to the certificate holders of the society.