N.H. Rev. Stat. Ann. § 21-J:43 - Authority to Enter Into Written Installment Payment Agreements.

The department may enter into written installment payment agreements if it determines that the agreement facilitates collection of delinquent taxes, penalties, and interest owed. The department may modify or terminate an installment payment agreement if it determines that the financial condition of the taxpayer has sufficiently changed or that the taxpayer has not complied with the terms of the installment agreement. The department shall give written notice to the taxpayer at least 30 days before the action terminating or modifying the installment payment agreement.