From: Rabbi Moshe Sofer
To: Unknown recipient
A supplementary bequest document signed only by the deceased's wife and eldest son — not the shechiv mera himself — was authenticated by witnesses with only hearsay knowledge. The Chasam Sofer rules that the signatories cannot retract their own signatures but that the document cannot override the prior endowment bequest to the poor, since the only witnesses to the alleged retraction are disqualified interested parties. As a practical resolution, all four adult sons voluntarily undertook to pay the uncle four gold coins weekly, with all past claims waived.
Source: Shu"t Chasam Sofer CM §49