Shulchan Arukh Choshen Mishpat · Siman 53

English

1. Not To Modify the Document, 1 Seif: If a person has a document against his friend for one maneh and he says to modify it to two documents of 50 each or if he has two documents of 50 each and says to make one document of 100 for him, we would not listen to him. RAMA: It is forbidden to modify the document, even if they know that the first loan has not been paid back, unless they have the consent of the borrower. (HaMagid, Perek 23; Rabbeinu Yerucham) Even if a lender has one document of 100 and says to tear it up and replace with a document for 50, we would not listen to him, because the borrower may have paid back the 100 and the lender gave him a receipt and now the lender will produce the document of 50 and say this is a different document and he will be able to collect with it.