Okla. Stat. tit. 12A, § 2-209
Oklahoma Code Comment
(1) This changes previous Oklahoma law. Consideration has previously been necessary to make an agreement to modify a contract binding. State ex ref. West v. City of Sapulpa, 58 Okl. 550, 160 P. 489 (1916); Smith v. Minneapolis Threshing Mach. Co., 89 Okl. 156, 214 P. 178 (1923).
(2) This changes previous Oklahoma law. 15 O.S. § 237, which provides: "A contract in writing may be altered by a contract in writing, or by an executed oral agreement, and not otherwise.", is repealed by implication in so far as it is inconsistent with this provision. 12A O.S. § 10-102.
(3) Previous Oklahoma law is in accord. Price v. McDowell, 52 Okl. 608, 153 P. 649 (1915).
(4) This has not been clearly announced in previous Oklahoma decisions, but see Mitchell v. Spurrier Lumber Co., 31 Okl. 384, 124 P. 10 (1912); Campbell v. Faye, 145 Okl. 213, 292 P. 7 (1930).
(5) There are no Oklahoma decisions.