Tex. Health & Safety Code § 265.046

Any bonds issued under this subchapter may be refunded by the issuance of refunding bonds in the manner provided by this subchapter for the issuance of other bonds, except the refunding bonds may be issued to be exchanged for the bonds being refunded. If the refunding bonds are issued to be exchanged, the comptroller shall register the refunding bonds and deliver them to each holder of the bonds being refunded as provided by the proceedings authorizing the refunding bonds. The exchange may be made in one delivery or several installment deliveries.