Okla. Stat. tit. 12A, § 12A-2A-407: Irrevocable Promises; Finance Leases

IRREVOCABLE PROMISES; FINANCE LEASES

(1) In the case of a finance lease that is not a consumer lease

the lessee's promises under the lease contract become irrevocable

and independent upon the lessee's acceptance of the goods.

(2) A promise that has become irrevocable and independent under

subsection (1) of this section:

(a) is effective and enforceable between the parties, and

by or against third parties including assignees of the

parties, and

(b) is not subject to cancellation, termination,

modification, repudiation, excuse, or substitution

without the consent of the party to whom the promise

runs.

(3) This section does not affect the validity under any other

law of a covenant in any lease contract making the lessee's promises

irrevocable and independent upon the lessee's acceptance of the

goods.