N.H. Rev. Stat. Ann. § 383-B:4-402

A depository bank doing business in this state may continue to recognize the power of an attorney-in-fact authorized in writing to make withdrawals either in whole or in part from the account of a depositor, whether a minor or adult, until it receives written notice or is on actual notice of the revocation of his or her authority. No depository bank shall be liable for damages, penalties, or tax by reason of any payment made under this section.