In Wachovia Bank v. Rubish, 306 N.C. 417, 424, 293 S.E.2d 749, 754 (1982), the Supreme Court of North Carolina discussed the elements needed for a party to assert promissory estoppel as a ground for waiver: The use of "estoppel" as a ground for "waiver" sometimes leads to confusion as to exactly what must be proved by the party asserting the estoppel. This is illustrated in the instant case by the defendant's pleading and the trial court's instructions on estoppel. In order to prove a waiver by estoppel defendant need not prove all elements of an equitable estoppel, for which proof of actual misrepresentation is essential; neither need he prove consideration to support the waiver. Rather, he need only prove an express or implied promise by Wachovia or Mr. Baker to waive the notice provision and defendant's detrimental reliance on that promise. Wachovia Bank, 306 N.C. at 427, 293 S.E.2d at 755-56. The Supreme Court held the defendant "bore the burden of establishing his affirmative defenses" of waiver and promissory estoppel. Thus, since our Supreme Court previously determined promissory estoppel is an affirmative defense, we now determine whether defendant waived this affirmative defense.