§ 907. Pleadings; subsequent pleading containing cause of action. (a)
Counterclaim. The plaintiff may reply to a counterclaim but shall not be
required to do so except by court order. If the plaintiff elects
voluntarily to reply, he shall do so within ten days after service of
the answer containing the counterclaim. In the absence of a reply the
allegations of the counterclaim shall be deemed denied by the plaintiff.
An answer containing a counterclaim against the plaintiff and another
person shall be replied to by such other person, as required by CPLR §
3019 (d), within the time provided in § 402 of this act, based upon the
time and method of service.

(b) Cross-claim. A cross-claim shall be answered within ten days after
the answer containing it is served.

(c) Third-party claim and claim by defendant stakeholder. A
third-party complaint, and an interpleader complaint served by a
defendant stakeholder under CPLR § 1006 (b), shall be answered within
the time provided in § 402 of this act, based upon the time and method
of service.