N.H. Rev. Stat. Ann. § 40:16

When irregularities or procedural defects in the actions of a local political subdivision are discovered in a local political subdivision using the official ballot, the local political subdivision may, on the authority of the governing body, call a special meeting for the exclusive purpose of curing such defect according to RSA 31:5-b with a single session for deliberating and voting to cure such defect.