Section 909. Pleadings; amended and supplemental

(a)  A party may amend his pleading once without leave of court at any
  time before the period for responding to it expires, or within ten  days
  after  its  service  or  the  service of a pleading responding to it. An
  amended pleading which requires a responsive pleading shall be responded
  to within ten days after it is served, or  within  ten  days  after  the
  expiration  of  the period during which the original pleading could have
  been responded to, whichever is later.
    (b) Except as provided in  subdivision  (a),  the  CPLR  shall  govern
  amended and supplemental pleadings in this court.