Tex. Education Code § 45.035

Revenue bonds issued by a board, city council or commission, or commissioners court under this subchapter and revenue bonds issued by a board, city council or commission, or commissioners court under other law and payable from revenues from facilities described by Section 45.031 may be refunded or otherwise refinanced by the board, city council or commission, or commissioners court, and in that case all appropriate provisions of this subchapter apply to the refunding bonds. In refunding or otherwise refinancing any such bonds, the board, city council or commission, or commissioners court may, in the same authorizing proceedings, refund or refinance bonds issued pursuant to this code and bonds issued pursuant to any other law, may combine all refunding bonds and any other additional new bonds to be issued under this chapter into one or more issues or series of bonds, and may provide for the subsequent issuance of additional parity bonds, or subordinate lien bonds, or other type of bonds. All refunding bonds must be issued and delivered under the terms set forth in the authorizing proceedings.