N.H. Rev. Stat. Ann. § 35:16

After the purpose for which a capital reserve fund is established has been determined, no change shall be made in the purpose for which said fund may be expended unless and until such change has been authorized by a vote of 2/3 of all the voters present and voting at an annual town or district meeting, in the case of a town or district, or by vote of 2/3 of the entire membership of a county delegation, in case of a county, or by unanimous vote of the water board or commissioners of the water department, in the case of a water works department, as provided in RSA 35:7.