Reference for Bava Metzia 38:9

מתקיף לה רב זביד והא אידי ואידי דייתקאות קא תני אלא אמר רב זביד הא והא בשכיב מרע ולא קשיא הא ביה והא בבריה

as it may be that you did write it for him but did not give it to him, and that you gave it to a different person instead, and now you have changed your mind again. Now, if you have not really given it to a different person, and you now wish to give it to this person, write him now another document and give it to him — for if you [formerly] did give [a document] to another person he will suffer no loss [because of the document you will write now], as [the person who holds the document with] the earlier date will be entitled to the gift.<span class="x" onmousemove="('comment',' As a healthy person cannot invalidate a document by a later document. ');">⁷</span>

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