Summary

Yosef Karo Shulchan Aruch — Choshen Mishpat 45

No other person or other head of court or scribe is permitted to do this. The witness much read the document word for word. There are those that say that two may read in front of the witnesses and the witnesses will sign. If the witnesses do not understand the language of the document, those reading it should translate the document and the witness can sign. This seems to me to be the primary ruling. There are those that say we can read in front of the public and have the witnesses sign because people are afraid of lying in public so it has the status of the head of court with his scribe.
Source: Wikisource

Yosef Karo Shulchan Aruch — Choshen Mishpat 45

Therefore, witnesses should not sign on an erased document unless it was erased in their presence because otherwise we are concerned that the place to sign was erased twice and the place of the document was only erased once, and when the party erases the document a second time and writes what he wants, it will come out that the document and place of signature have both been erased the same two times. They must be careful to have everything erased on the same day, because a one-day old erasure is not comparable to a two-day old erasure.
Source: Wikisource

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