C.R.S. § 4-9-209

(a) Except as otherwise provided in subsection (c) of this section, this section applies if: (1) There is no outstanding secured obligation; and (2) The secured party is not committed to make advances, incur obligations, or otherwise give value. (b) Within ten days after receiving a signed demand by the debtor, a secured party shall send to an account debtor that has received notification under section 4-9-406 (a) or 4-12-106 (b) of an assignment to the secured party as assignee a signed record that releases the account debtor from any further obligation to the secured party. (c) This section does not apply to an assignment constituting the sale of an account, chattel paper, or payment intangible.