UCC § 2-209
Modification, Rescission and Waiver
(1) An agreement modifying a contract within this Article needs no consideration to be binding. (2) A signed agreement which excludes modification or rescission except by a signed writing cannot be otherwise modified or rescinded, but except as between merchants such a requirement on a form supplied by the merchant must be separately signed by the other party. (3) The requirements of the statute of frauds section of this Article (Section 2-201) must be satisfied if the contract as modified is within its provisions. (4) Although an attempt at modification or rescission does not satisfy the requirements of subsection (2) or (3) it can operate as a waiver. (5) A party who has made a waiver affecting an executory portion of the contract may retract the waiver by reasonable notification received by the other party that strict performance will be required of any term waived, unless the retraction would be unjust in view of a material change of position in reliance on the waiver.
Professor's notes
Elements: (1) an agreement modifying a contract within the UCC needs no consideration to be binding; (2) a signed agreement excluding modification or rescission except by a signed writing cannot be otherwise modified or rescinded, but a between-merchants form requires separate signature; (3) the requirements of the SoF (§ 2-201) must be satisfied if the contract as modified is within its provisions; (4) although attempt at modification or rescission does not satisfy (2) or (3), it can operate as a waiver; (5) a party who has made a waiver affecting an executory portion of the contract may retract it by reasonable notification unless retraction would be unjust because of a material change of position in reliance.
Common misunderstanding: students think (1) abolishes all policing of modifications for goods. It does not: § 1-304 good faith still applies. Coerced "hold-up" modifications fail under good faith even without the pre-existing duty rule. The UCC traded chok (mechanical consideration check) for mishpat (substantive good-faith review).
Cases that operationalize this rule
Text
UCC § 2-209. Modification, Rescission and Waiver.
(1) An agreement modifying a contract within this Article needs no consideration to be binding.
(2) A signed agreement which excludes modification or rescission except by a signed writing cannot be otherwise modified or rescinded, but except as between merchants such a requirement on a form supplied by the merchant must be separately signed by the other party.
(3) The requirements of the statute of frauds section of this Article (Section 2-201) must be satisfied if the contract as modified is within its provisions.
(4) Although an attempt at modification or rescission does not satisfy the requirements of subsection (2) or (3) it can operate as a waiver.
(5) A party who has made a waiver affecting an executory portion of the contract may retract the waiver by reasonable notification received by the other party that strict performance will be required of any term waived, unless the retraction would be unjust in view of a material change of position in reliance on the waiver.
Note: The supplement reproduces this provision as N.H.R.S.A. 382-A (New Hampshire’s codification of the UCC). The text reflects the post-2022 UCC Article 2 amendments as adopted in New Hampshire.