20 Pa.C.S. § 3138

If a later will or codicil is submitted to the register for probate within three months of the testator's death but after the register shall have probated an earlier instrument, the register, after such notice as he deems advisable, but with at least ten-days' notice to the petitioner who presented the probated instrument if he has not requested probate of the later will or codicil, shall have power to open the probate record, receive proof of the later instrument or instruments and amend his probate record.