N.H. Rev. Stat. Ann. § 100-A:19-d

Notwithstanding any other provision of law, any retirement system member who has creditable service in both group I and group II with at least 10 years combined creditable service, and who has attained an age which is at least 45 for members who commenced service before July 1, 2011, or at least 50 for members who commenced group II service on or after July 1, 2011, and group II members who have not attained vested status prior to January 1, 2012, shall be as provided in the transition provisions in RSA 100-A:5, II(d), and is within 10 years of the minimum age set forth in RSA 100-A:19-b, may elect to retire and have benefits commence immediately as a reduced split-benefit service retirement allowance. Application shall be as provided in RSA 100-A:5, I(c). The allowance shall be determined as a split-benefit service retirement allowance in accordance with RSA 100-A:19-c, and the total combined split-benefit service allowance shall be reduced by the percentages shown in RSA 100-A:5, I(c), based on the total combined length of creditable service, for each month by which the date on which benefits commence precedes the month after which the member attains the minimum age set forth in RSA 100-A:19-b.