N.H. Rev. Stat. § 41:8-e
If a town votes to enlarge or to decrease its board of selectmen the change does not take effect in either case until the first annual meeting following the meeting at which the questions were acted upon. If the town votes to enlarge the board to 5 members, at the first annual meeting following the meeting when the action was taken the town shall elect 2 members for a 3-year term and one member for a one-year term. At the next succeeding annual meeting 2 members shall be elected for a 3-year term, at the next following annual meeting one member shall be elected for a 3-year term, and at succeeding annual meetings members shall be elected to fill the vacancies regularly occurring. If a town votes to decrease its board to 3 members, at the annual meeting following the meeting at which it so voted, the terms of office of all members of the board of selectmen shall end and the town shall elect 3 members of the board of selectmen, one for one year, one for 2 years, one for 3 years and at all succeeding annual meetings shall elect a member to the board for a 3-year term.
RSA 41:8-e
1967, 325:1, eff. Sept. 1, 1967.