68 Pa. Stat. § 183
The enactment, by the twenty-first section of the act of April 22, 1850, enacting that no redeemable ground rent shall become a perpetual encumbrance by failure to pay the redemption money within the period fixed for its redemption, shall be taken and construed to enable any trustee or trustees, and others having power to release and extinguish such ground rent, theretofore reserved, but then redeemable, or since reserved or hereafter to be reserved with the privilege of redemption within a specified time, to accept the redemption moneys, and to execute a release and extinguishment of such ground rent, as if such period allowed for such redemption had not expired, with the same effect as if done within such period; and all releases and extinguishments of ground rents, heretofore made by such parties under such circumstances since the date of said enactment, shall be taken to have the same validity and effect as if made by them within the period specified for redemption.
68 P.S. § 183