Colo. Rev. Stat. § 32-11-564
(1) Subject to the provisions of section 32-11-559, any general obligation bonds or special obligation bonds of the district issued in accordance with the provisions of this article or any other law, and payable from any pledged revenues and any general obligation bonds of the district so issued but not payable from pledged revenues may be refunded on behalf of the district by the board, by the adoption of a resolution by the board, and by any trust indenture or other proceedings pertaining thereto, authorizing without any election the issuance of refunding bonds to refund, pay, and discharge all or any part of such outstanding bonds of any one or more or all outstanding issues:
Source: L. 69: p. 782, § 106. C.R.S. 1963: § 89-21-106.