Okla. Stat. tit. 12A, § 12A-2A-404: Substituted performance

SUBSTITUTED PERFORMANCE

(1) If without fault of the lessee, the lessor and the

supplier, the agreed berthing, loading, or unloading facilities fail

or the agreed type of carrier becomes unavailable or the agreed

manner of delivery otherwise becomes commercially impracticable, but

a commercially reasonable substitute is available, the substitute

performance must be tendered and accepted.

(2) If the agreed means or manner of payment fails because of

domestic or foreign governmental regulation:

(a) the lessor may withhold or stop delivery or

cause the supplier to withhold or stop delivery unless the lessee

provides a means or manner of payment that is commercially a

substantial equivalent; and

(b) if delivery has already been taken, payment by

the means or in the manner provided by the regulation discharges the

lessee's obligation unless the regulation is discriminatory,

oppressive, or predatory.