68 Pa. Stat. § 126
All persons so holding or having so held under any such donee, and the survivor or survivors of any such as so held in common, may either before or after alienation by them of the whole or any part of the premises so as aforesaid to them conveyed, bar such implied or supposed entailment thereof, as fully and completely as the donee might have barred the same in pursuance of any existing law, in the manner following, viz.: They shall execute under the proper hand and seal of each a declaration of their purpose to bar any supposed entailment of the premises mentioned therein, which declaration shall be duly acknowledged by them before some person authorized to take acknowledgment of deeds, and thereupon shall be recorded by the recorder of deeds of the proper county, and from the filing thereof by such recorder such supposed entailment shall be held fully and completely barred.
68 P.S. § 126