(dissenting). I respectfully dissent. The party’s agreement “is an independent contract which is subject to the principles of contract interpretation” (De Gaust v De Gaust, 237 AD2d 862). Thus, when the language is clear and unambiguous, the court is required “to ascertain ‘the intent of the parties * * * from within the four corners of the instrument, and not from extrinsic evidence’ ” (Keith v Keith, 241 AD2d 820, 822, quoting Rainbow v Swisher, 72 NY2d 106, 109; accord, Von Buren v Von Buren, 252 AD2d 950).
The application of these principles to the separation agreement under review reveals that the parties plainly and unambiguously agreed that the marital portion of plaintiffs pension as determined by the Majauskas formula (see, Majauskas v Majauskas, 61 NY2d 481) was to be equally divided between the parties as, if and when received. The sole issue on which the parties were unable to agree concerned the payment option. Accordingly, the agreement vests authority in Supreme Court, at the time of the divorce action, to “determine whether *809[plaintiff! shall be obligated to take a survivor option and if so, what option”.
In my view, Supreme Court properly chose an option but then exceeded the authority found in the separation agreement by adjusting the payout of the marital share of the pension resulting in plaintiff receiving more than one half of the marital share during his lifetime, in effect, altering the 50% figure in the formula contained in the contract.
Accordingly, I would modify Supreme Court’s order and judgment by reversing that portion of the formula adopted by Supreme Court which does not divide the marital share of plaintiff’s pension 50% to each of the parties, and direct that 50% of the marital share be paid to each of the parties, and as so modified, affirm.
Ordered that the order and judgment are affirmed, without costs.