Okla. Stat. tit. 62 § 57.71
The Commission may issue bonds hereunder for the purpose of refunding any obligations issued under the provisions of this act. Such bonds may either be sold or delivered in exchange for outstanding obligations. If sold, the proceeds may be either applied to the payment of the obligations refunded or deposited in escrow for the retirement thereof. Nothing herein shall be construed to authorize the refunding of any outstanding obligations which are not either maturing, or callable for redemption under their terms, or voluntarily surrendered by their holders for cancellation, unless the Commission covenants that sufficient funds to pay all remaining interest and principal payments of outstanding obligations when due will be placed in escrow for such purpose in the State Treasury at the time of delivery of and payment for the new bonds issued hereunder. All bonds issued under this section shall in all respects be authorized, issued and secured in the manner provided for other bonds issued under this Act, and shall have all the attributes of such bonds. The Commission may provide that any such refunding bonds shall have the same priority of payment and be paid from the same revenues in the manner enjoyed by the obligations refunded thereby.
Okla. Stat. tit. 62, § 57.71