C.R.S. § 7-106-302

(1) A corporation may acquire its own shares, and, except as provided by section 7-117-101 (6), shares so acquired constitute authorized but unissued shares. (2) If the articles of incorporation prohibit the reissuance of acquired shares: (a) The number of authorized shares is reduced by the number of shares acquired by the corporation, effective upon amendment to the articles of incorporation; and (b) The corporation shall deliver to the secretary of state, for filing pursuant to part 3 of article 90 of this title, articles of amendment to the articles of incorporation, which are effective without shareholder action, that state: (I) The domestic entity name of the corporation; (II) The reduction in the number of authorized shares, itemized by class and series; and (III) The total number of authorized shares, itemized by class and series, remaining after reduction of the shares.