C.R.S. § 4-9-624

(a) A debtor or secondary obligor may waive the right to notification of disposition of collateral under section 4-9-611 only by an agreement to that effect entered into and signed after default. (b) A debtor may waive the right to require disposition of collateral under section 4-9-620 (e) only by an agreement to that effect entered into and signed after default. (c) Except in a consumer-goods transaction, a debtor or secondary obligor may waive the right to redeem collateral under section 4-9-623 . Any such waiver must be by an agreement to that effect entered into and signed after default.