72 Pa. Stat. § 5860.603
Any owner or lien creditor of the owner may, at the option of the bureau, prior to the actual sale, (1) cause the property to be removed from the sale by payment in full of taxes which have become absolute and of all charges and interest due on these taxes to the time of payment, or (2) enter into an agreement, in writing, with the bureau to stay the sale of the property upon the payment of twenty-five per centum (25%) of the amount due on all tax claims and tax judgments filed or entered against such property and the interest and costs on the taxes returned to date, as provided by this act, and agreeing therein to pay the balance of said claims and judgments and the interest and costs thereon in not more than three (3) instalments all within one (1) year of the date of said agreement, the agreement to specify the dates on or before which each instalment shall be paid, and the amount of each instalment. So long as said agreement is being fully complied with by the taxpayer, the sale of the property covered by the agreement shall be stayed. But in case of default in such agreement by the owner or lien creditor, the bureau, after written notice of such default given by United States mail, postage prepaid, to the owner or lien creditor at the address stated in the agreement, shall apply all payments made against the oldest delinquent taxes and costs, then against the more recent. If sufficient payment has been made to discharge all the taxes and claims which would have caused the property to be put up for sale, the property may not be sold. If sufficient payment has not been received to discharge these taxes and claims, the bureau shall proceed with the sale of such property in the manner herein provided either at the next scheduled upset sale or at a special upset sale, either of which is to be held at least ninety (90) days after such default. If a party to an instalment agreement defaults on the agreement, the bureau shall not enter into a new instalment agreement with that person within three (3) years of the default.
72 P.S. § 5860.603