Mont. Code Ann. § 75-6-327

If the authority has issued bonds under the provisions of this part, it may by resolution issue refunding bonds for the purpose of retiring or refinancing outstanding bonds, together with any unpaid interest on the bonds and any redemption premium. All of the provisions of this part relating to the issuance, security, and payment of bonds apply to the refunding bonds. However, the bonds are subject to the provisions of the proceedings that authorized the issuance of the bonds to be refunded.