Section 504. Amendment of Claim.--A claim may be amended from time to time without prejudice to intervening rights by agreement of the parties or by leave of court, except that no amendment shall be permitted after the time for filing a claim has expired which undertakes to:
(1) substitute a different property than that described in the claim; or
(2) substitute a different party with whom the claimant contracted; or
(3) increase the aggregate amount of the claim.