Okla. Stat. tit. 12A, § 1-9-209
Oklahoma Code Comment
This section also is new and like revised section 9-208 addresses a situation not explicitly covered under present law: the case where an account, chattel paper or general intangible has been assigned and the account debtor has been notified to pay the assignee, and now should be released by the assignee. Sales are not covered, nor are persons obligated on negotiable instruments (even if the instrument is part of chattel paper) (see revised sections 9-102(a)(3) and 3-602 ) .
The sanction for violation appears in revised section 9-625(b) and (d) .