N.H. Rev. Stat. Ann. § 275:68

Employers shall be exempted from the provisions of RSA 275:67 by written agreement between the employer and employee, made without coercion or pressure, provided the agreement is submitted to the commissioner of the department of labor. The agreement may be terminated by the employee by written notice to the employer and the commissioner of the department of labor. Said termination shall be effective 14 days after notice is provided.