Cal. Ins. Code § 11026

A domestic society may amend its articles of incorporation, constitution, or laws, in accordance with the provisions thereof, by action of its supreme legislative or governing body at any regular or special meeting. If the articles of incorporation, constitution, or laws so provide, amendment may be made by referendum. A referendum may be held in accordance with the provisions of the society’s articles of incorporation, constitution, or laws by the vote of the voting members of the society, by the vote of delegates or representatives of voting members or by the vote of local lodges or branches. No amendment submitted for adoption by referendum shall be adopted unless, within six months from the date of the amendment’s submission, a majority of the members of the society have signified their consent to the amendment by one of the methods herein specified.