Opinion by
Kephart, J.,
The plaintiff was the owner of a house and lot of ground in Lancaster County. On November 9, 1907, being indebted to the defendant she and her husband made a deed of conveyance to the defendant, and at the same time entered into an agreement out of which the present controversy arises. The agreement provided that when the plaintiff had paid to the defendant the *516sum of $924.59, with all tax rates, charges and assessments against the property, and the charges for keeping an insurance against fire upon the buildings, and also paid all rents equal to the interest on the principal sum, the defendant should reconvey the said property to the plaintiff, her heirs and assigns. The principal sum was $650.59 and was to be paid before April, 1908; the balance was to remain as a dower charge. The rent during the period from November until April was to be paid on the first of each month. It was agreed that the plaintiff was to keep up at her own expenses the repairs to the said premises. It was expressly agreed that if default should be made at any time by the plaintiff in paying the rental or the principal sum or the taxes, then the contract of sale should become absolutely null and void, and for the collection of the rent it was provided that a landlord’s warrant might be issued. A second proviso stipulated that in case the rent and all charges had been paid and a portion of the principal had been paid by the plaintiff and the defendant should sell the property to someone other than the plaintiff, then he was to account to the plaintiff for any difference between the purchase price and the balance of the claims which the defendant had against her. The third provision, and the one which is the most difficult, provides that the agreement may be terminated by the defendant giving six months’ previous notice and demanding payment of the said principal sum, with all other claims and demands thereunder, if this agreement continued beyond April 1, 1908. By the terms of the agreement, there was but one method to continue beyond April 1, 1908, and that was by advance payments; and had there .been a default on April 1,1908, with no subsequent dealings between the parties to continue the contract, or no act of the defendant which might constitute a waiver, then the defendant without notice could have sold the property without being liable to the plaintiff. Appellant urges that all plaintiff’s rights under the contract were forfeited. A forfeiture *517is abhorred in law as in equity, and where the rights of one of the parties will be injured by so- declaring it, courts will not be slow to seize on a reasonable opportunity to prevent the forfeiture. “Where a contract provides ‘in case the said party of the second part doth not make payment as above specified at the time herein stated then this agreement is to be null and void and all parties are to be released from all liabilities herein and all money previously paid forfeited/ a failure to make the payments at the stipulated time does not of its own force, terminate the contract. The seller must declare the forfeiture and if he fails to do so and retains the right to enforce the contract against the purchaser to buy, he equally keeps alive his own obligation to sell.” Weaver v. Griffith, 210 Pa. 13; King’s Est., 215 Pa. 59. The appellant continued the appellee in the possession of the property for a long period of time after April 1, 1908, and so conducted himself with relation to the contract which with the reasons underlying its execution were sufficient to submit to the jury the question as to whether or not there was a waiver of the right to forfeit on April 1, 1908. There is an abundance of authority that the parties may, by a course of conduct subsequent to an agreement, substitute new provisions or change or alter an agreement already existing, or continue in life what otherwise would have been a forfeited right. Assuming then that the agreement was continued, what rights did this appellee have? The appellant contends that the provision as to the failure to pay the rent mentioned in the first proviso created such a condition as permitted him to sell without the six months’ notice; but here we are met with the plaintiff’s testimony that she paid the rent, taxes, repairs, and insurance and we cannot determine from the verdict that the jury did not so find; and further, the defendant could have distrained for the balance of the rent due, which right he did not see fit to exercise. Whatever may have been his right to distrain for the rent, if the appellant had permitted the appellee *518to become in arrears in rent he could only annul the contract of.sale by giving the six months’ notice. She was thus given a chance to redeem the property in case she so desired. If the plaintiff paid the rent as she testified to, of course, there can be no question that the contract to sell was not dead. This six months’ notice was not effective only in case of advance payments made before April 1,1908, as mentioned in the second provision of the contract; that the contrary was intended may be taken from the language used in connection with this notice “demanding payment of said principal sum with all other claims and demands if this agreement continue beyond April 1, 1908.” He realized that his contract could not be avoided except by giving this notice, as he attempts to show by his evidence that he did give it; but the jury found adversely to this testimony. When the agreement was continued beyond April 1st plaintiff must be given an opportunity to repurchase the property. That right was denied her and she now claims the difference between the sale made and the amount due to the defendant, and the jury fixed that sum at $279.00, after deducting all of the defendant’s claim. As to the method adopted in arriving at this particular sum, no request was made by counsel for any different measure of damages or method of ascertaining the sum due to the plaintiff, and as the case was tried out on the theory of accounting, this court will not disturb that result. The defendant submitted a counterclaim as against the amount claimed by the plaintiff, which counterclaim exceeded the price at which the property was subsequently sold; it was apparently his intention to treat the contract as assuring to the defendant that all he desired was reimbursement after all his claims had been paid.
The question of jurisdiction was not raised in the court below at the arguments in this court nor in the paper books and is not passed upon.
The assignments of error are overruled and the judgment is affirmed.