Opinion by

In this action of assumpsit the plaintiffs sought to recover damages for the breach of a certain contract made in May, 1907, whereby the plaintiffs agreed to deliver, and the defendants agreed to accept and pay for, twenty-five cases of cambric at the price of seven and five-eighths cents per yard. A memorandum of the terms of the contract was made by the plaintiffs and delivered to the defendants, by which it appears that the goods were to be delivered in the following September, October, November and December, and that the defendants were to have sixty days after delivery for payment and were *74to be allowed a discount of two per cent, if payment was made within that time, and an additional discount of one per cent, if made within ten days. Before the end of December, 1907, the defendants had taken and paid for, at the contract price, eleven cases of the goods. The circumstances show that both parties waived strict compliance with the terms of the contract in respect to time, but up to February 10, 1908, both regarded it as binding upon them in all other respects. After that date the defendants ordered three more cases of cambric to be shipped to them. These orders were filled and the plaintiffs billed the goods at six and one-half cents per yard, on which basis they were paid for. About the middle of April the plaintiffs pressed the defendants to take the rest of the cambric called for by. the contract. The latter replied that the contract of May 15, 1907, had been .canceled and that they were under no obligation to take more goods. We shall refer to this later. After some correspondence on the subject the plaintiffs notified defendants that unless they took the remainder of the cambric without further delay they would sell it in the market and hold them for any loss that might result. Subsequently these goods were sold by the plaintiffs at prices which realized’ $753.88 less than they would have yielded at the contract price. Plaintiffs claim to recover this sum and a commission of six per cent for expenses of resale. The foregoing statement of undisputed facts is taken substantially from the opinion of the learned judge refusing a new trial.

The principal controversy arises out of what took place at a conference on the afternoon of February 10, 1908, between James Bryson, one of the plaintiffs, and Morris Stone, one of the defendants. The testimony on the subject was in conflict and the court submitted to the jury the determination of the question whether the version given by Bryson or that given by Stone was the correct one, but instructed them that if they found the latter to be correct their verdict should be for the defendants. It is important, therefore, to see what his version was. He says that he made the proposition that if the plaintiffs would extend the time to take the remaining cases of *75cambric and permit the defendants to take them as their business would allow them to do they, the defendants, would pay for them the prevailing prices in the market at the time the goods were delivered, and that Bryson assented to this proposition. This is the substance of the defendants’ testimony in chief upon tins subject. We quote now from his cross-examination: “Q. There were fourteen cases, and when were you to take them? A. I agreed with Mr. Bryson to take them as soon as my business allowed me. Q. During what year, in what particular time? A. There was no time mentioned. Q. You were to take them just whenever you wanted? A. Yes, as the business allowed it. . . . Q. Who was to fix the date when the cases,, when the rest of the goods were to be delivered? A. Nobody; the business conditions. Q. Whose business conditions? A. Of this country. Q. Whose business conditions? A. Mine.” The appellants’ counsel argues that such an agreement lacks the certainty, definiteness and mutuality which are necessary constituents of a legal obligation, and the authorities cited by him tend to support this proposition. The defendants seem to have taken the same position, for on April 18, 1908, they wrote to the plaintiffs as follows: “Yours of the 17th instant is at hand, and in reply to same beg to state that we have no goods on contract with you, the goods in question have been canceled some time ago. And if you wish to continue to do business with us you will have to submit new samples with prices.” It was not until after suit was brought that the defendants took the position that the supplementary agreement of February 10, 1908, was in force and would be carried out by them. Speaking of the foregoing letter the learned judge, in his opinion refusing a new trial, says that it is not inconsistent with the defendants’ testimony in the case, because the agreement of February 10, 1908, by reason of its lack of certainty, imposed no contractual obligation on the defendants. If that be true, and we are inclined to the opinion that it is the correct view, it is difficult to seé how it could in and of itself be held as matter of law to have superseded the original contract.. But it is argued that the case before us is one of cancellation by mutual releases *76and hence it is immaterial whether or not the new agreement created an enforceable obligation. This assumes that there was a cancellation of the original agreement. That the parties to a contract, so long as it is executory, may at any time rescind it, either in whole or in part, by mutual consent, and that the surrender of their mutual rights is sufficient consideration, is well settled: Flegal v. Hoover, 156 Pa. 276; Reber v. Brownback, 27 Pa. Superior Ct. 471. But there can be no cancellation unless the intention of the parties be clearly shown. This may be by express agreement to that effect, or it may be shown by the circumstances of the case. But it must be shown. We assume that there may have been a cancellation of the original contract, although the agreement of February 10, 1908, did not create an enforceable obligation. The difficulty we find in the case is in concurring with the learned judge’s instructions that, if the defendants’ version of the transaction was the correct one, it was conclusive of the question of cancellation. In our view of the case it was evidence to be taken into consideration with all that had gone before and came afterwards upon the question whether the contract was rescinded by mutual agreement of the parties, but was not of itself conclusive upon that question. Therefore, the assignments of error, in so far as the instructions therein recited upon this subject are in conflict with this view, are sustained.

Upon the question of the right to recover commissions on a resale, the learned judge instructed the jury that the proofs were insufficient to sustain the claim, and in that conclusion we concur.

• We have not gone into as full discussion of the case as might be warranted, because we think it is very clearly stated in the opinion of the learned judge refusing a new trial. We have endeavored to point out the reasons for our inability to agree with him as to the legal effect of the agreement entered into on February 10, 1908, assuming the defendants’ version of what took place in the afternoon of that date to be correct.

The judgment is reversed and a venire facias de novo is awarded.