S.C. Code Ann. § 36-9-624: Waiver.

(a) A debtor or secondary obligor may waive the right to notification of disposition of collateral under Section 36-9-611 only by an agreement to that effect entered into and authenticated after default.

(b) A debtor may waive the right to require disposition of collateral under Section 36-9-620(e) only by an agreement to that effect entered into and authenticated after default.

(c) Except in a consumer-goods transaction, a debtor or secondary obligor may waive the right to redeem collateral under Section 36-9-623 only by an agreement to that effect entered into and authenticated after default.