Section 651. Reduction of retirement age

a. A member described in section
  six hundred fifty of this article may,  subject  to  the  provisions  of
  subdivision  b  of  this section (and notwithstanding the provisions for
  benefit reduction contained in subdivision a  of  section  four  hundred
  forty-two  and  subdivision  c  of  section  five  hundred  four of this
  chapter), retire without reduction of  his  or  her  service  retirement
  benefit  prior  to  the  attainment  of  the  normal  retirement  age in
  accordance with the following schedule:
    (i) For each full  year  of  covered  employment  occurring  prior  to
  January   first,   nineteen  hundred  seventy-one,  his  or  her  normal
  retirement age shall be reduced by six months; and
    (ii) For each full year  of  covered  employment  occurring  prior  to
  January  first,  two  thousand  nine  which  is  subsequent  to December
  thirty-first, nineteen hundred seventy, his or her normal retirement age
  shall be reduced by four months.
    b. Provided however, that nothing herein:
    (i) Shall permit a member of  Tier  one  to  retire,  other  than  for
  disability,  prior  to  the attainment of age fifty, or a member of Tier
  two, three or four to retire, other than for disability,  prior  to  the
  attainment of age fifty-five; and
    (ii)  Shall  be construed to affect any other condition or requirement
  of any general, special or local law.