OPINION OF THE COURT
Lynch, J.The facts underlying this appeal by the plaintiff from an order dismissing her complaint are fully stated in the dissenting opinion. For the reasons stated in that opinion, we too would direct that Horace Bullard, president of the Whitehall Tenants’ Committee be joined as a party plaintiff. Otherwise, we would affirm.
A stipulation is in the nature of a contract and is subject to the rules governing contracts (Yonkers Fur Dressing Co. v Royal Ins. Co., 247 NY 435; Bond v Bond, 260 App Div *348781, mot for rearg and mot for lv to app den 261 App Div 835; see, also, McLaughlin, Practice Commentaries, McKinney’s Cons Laws of NY, Book 7B, CPLR C2104:l, p 560). Consequently, a stipulation must embody offered terms and arise from a valid acceptance of that offer.
The intention to accept must be manifested unequivocally (1 Williston, Contracts [3d ed], § 72), the acceptance must be of the terms stated in the offer, and if the offeree responds by adding provisions or making a counterproposal, the offer is deemed rejected (Wittwer v Hurwitz, 216 NY 259, mot for rearg den 217 NY 666; Machinery Utilities Co. v Fry, 224 App Div 392), rendering subsequent acceptance impossible (Hough v Brown, 19 NY 111, 115; Westwitt Realty Corp. v Burger, 212 App Div 622, 626).
Applying this fundamental law to the facts, we find untenable the dissent’s conclusion that the plaintiff and the intervening plaintiff validly accepted “albeit belated * * * the terms of the stipulation submitted by Ambassador”.
We consider, as does the dissent, that when the parties announced the settlement of the RPAPL article 7-A proceeding and stated that a stipulation would be reduced to writing, the draft submitted to the plaintiff-intervenor’s attorney by the defendants’ attorney to have been the latter’s offer of the terms of the stipulation settling their action. The offer was not accepted. Instead, it was returned with a number of provisions added. Whether a counteroffer or a modification, this must be deemed a rejection of the offer, and at that point the offer was dead. When, on the later motion to set aside the stipulation, the defendants insisted that their offer had embodied the terms leading to the settlement, the plaintiff-intervenor persisted in its rejection. At this point the offer was doubly dead. It was only when this action was commenced that the plaintiff and plaintiff-intervenor manifested any intent to accept the defendants’ terms. The acceptance, not simply “belated”, is far too late.
Ignoring the rejection made twice of the defendants’ terms, the plaintiff and plaintiff-intervenor contend that the defendants are estopped by their twice having offered them. An estoppel, however, may arise only “where the *349facts of the agreement are undisputed” (Matter of Dolgin Eldert Corp., 31 NY2d 1, 11). Here, the terms have always been in dispute.
We find it of no constraining import that there was a denial of the motion to vacate the discontinuance of the 7-A proceeding. The denial never reached the question of the existence of any underlying agreement; it arose solely on the technical ground that the mortgagee had not been made a party to the motion.
Order, Supreme Court, Bronx County (Callahan, J.), entered June 10,1983, dismissing the plaintiff’s complaint as against the defendants Ambassador Associates and Whitehall Realty Co. modified, on the law and on the facts, to the extent of directing that Horace Bullard, president of the Whitehall Tenants’ Committee, officially named the 3333 Henry Hudson Parkway Tenants’ Association, Inc., be joined as a party plaintiff and, as so modified, affirmed, without costs or disbursements.