N.H. Rev. Stat. Ann. § 171-A:7

Except for a person admitted involuntarily pursuant to RSA 171-B, a client at any time may seek a change in services or withdraw entirely from the service delivery system. A parent or legal guardian may seek a change of services for or withdraw entirely a minor or ward in his or her custody at any time, unless such minor has reached the age of majority. The administrator shall notify the area agency of any such withdrawal and may, if appropriate, indicate in the client's record that such withdrawal was against professional advice.