N.H. Rev. Stat. Ann. § 556:27

The probate court may authorize administrators and guardians to adjust by compromise or arbitration any controversy between them and persons making claims against the estates in their hands. The attorney general or the director of the register of charitable trusts shall be a necessary party to any agreement between an executor and creditors or legatees or heirs-at-law whenever such agreement may directly or indirectly affect a charitable interest, residuary or otherwise, created in any estate.