The effect of breach, both as a ground for treating the contract as discharged, and as giving rise to a right of action for damages, is modified by the doctrine of waiver, so called. As has already been pointed out, in connection with waiver of express conditions the term "waiver" was used at the early law of the act of a thief, in throwing away goods in his flight. The modern law waiver is usually said to be the intentional abandonment or relinquishment of a known right.1 The term is actually used to indicate the result of a number of different combinations of fact, rather than to indicate any definite means by which such result is brought about. The result, which is called waiver, is the giving up of an existing right; and when used with reference to a breach, it means, in some cases, the giving up of the right to treat the contract as discharged because of the breach of such contract by the adversary party;2 and in other cases it means the giving up of the right to maintain an action to recover damages because of such breach by the adversary party.3 Either of these results may be reached whenever the contract, or a right of action based on the contract, is discharged by voluntary agreement;4 and accordingly such subsequent agreement is frequently spoken of as a waiver. While discharge by a new contract is frequently referred to as waiver, waiver does not necessarily rest upon the existence of a new contract; and accordingly waiver of breach as a discharge may exist without any new and additional consideration.5

12 Peck v. Kansas City Metal Roofing & Corrugating Co., 96 Mo. App. 212, 70 S. W. 169; Ward v. American Health Food Co., 119 Wis. 12, 96 N. W. 388.

13 International Text-book Co. v. Jones, 166 Mich. 86, 131 N. W. 98.

14 Kinney v. Philadelphia Watch Case Co., 76 N. J. L. 735, 71 Atl. 269; Thompson Mfg. Co. v. Gunderson, 106

Wis. 449, 49 L. R. A. 859, 82 N. W. 299.

15 Milwaukee Boiler Co. v. Duncan, 87 Wis. 120, 41 Am. St. Rep. 33, 53 N. W. 232.

16 Kinney v. Philadelphia Watch Case Co., 76 N. J. L. 735, 71 Atl. 269.

17 McGregor v. Ross, 96 Mich. 103, 55 N. W. 658.

18 McGregor v. Ross, 96 Mich. 103, 55 N. W. 658.

If the party who is not in default has induced the adversary party to continue performance, or otherwise to alter his position, in reliance upon the continued recognition of the existence of such contract by the party who is not in default, the party who is not in default is not permitted to alter his position, and to claim that the contract is discharged, after the party originally in default has altered his position as by continuing performance of such contract.6 This result is frequently explained upon the theory of estoppel; and it has accordingly been said that waiver exists only where there is a valid new contract, whether under seal or upon a valuable consideration, or where there is estoppel.7 At the same time, as in the case of the waiver of express conditions,8 waiver of breach of a covenant is recognized in some jurisdictions in cases in which there is neither a new contract nor an estoppel.9

1 Waiver is "the intentional relinquishment of a known right." Griffith v. Newell, 69 S. Car. 300, 48 S. E. 259 [citing, Grocery Co. v. Moore, 63 S. Car. 184, 41 S. E. 88].

"Waiver is the voluntary abandonment or relinquishment by a party of some right or advantage." Draper v. Oswego County Fire Relief Association, 190 N. Y. 12, 82 N. E. 756 [quoted in Clark v. West, 193 N. Y. 349, 86 N. E. 1].

2 See Sec. 3038 et seq. 3 See Sec. 3062 et seq.

4 See Sec. 2446 et seq.

5 Mahaska County State Bank v. Crist, 87 la. 415, 54 N. W. 450.

6 Elgar v. Newhall, - Mass. -, 126 N. E. 661.

See Sec. 3040 et seq.

7 "Unless a waiver is under seal, or arises from conduct creating an estoppel, it must be supported by an agreement founded upon a valuable consideration." Frankfurt-Barnett Co. v. Prym Co., 237 Fed. 21, L. R. A. 1918A, 602 [citing, Emerson v. Slater, 63 U S. (22 How.) 29,16 L. ed. 360; Hastings v. Lovejoy, 140 Mass. 2C1, 54 Am. Rep. 462, 2 N. E. 776; Underwood v. Farmers' Joint Stock Ins. Co., 57 N. Y. 500; Atlantic Coast Line R. Co. v. Bryan, 109 Va. 523, 65 S. E. 30].

A waiver which is conditioned upon the happening of some future event is inoperative if such condition is broken.10