N.H. Rev. Stat. § 301:5
An association may amend its certificate of organization by the affirmative vote of 2/3 of the members voting thereon at any regular meeting, or at a special meeting called for that purpose, or if the association permits its members to vote on the basis of patronage, by the affirmative vote of a majority of the members and of 2/3 of the patronage, voting thereon. A written or printed notice of the proposed amendment and of the time and place of holding such meetings shall be delivered to each member, or mailed to his last known address as shown by the books of the association, at least 30 days prior to any such meetings. No amendment affecting the preferential rights of any outstanding stock shall be adopted until the written consent of the holders of 2/3 of the outstanding preference shares has been obtained. Amendments to the certificate of organization, when so adopted, shall be filed in accordance with the provisions of the preceding section.
RSA 301:5
1925, 33:7. PL 224 :5. RL 273:5. 1945, 150:1, eff. May 9, 1945.