The Book of Transactions (Kitab Al-Buyu`)

Muslim :: Book 10 : Hadith 3656

Ibn 'Umar (Allah be pleased with them) reported Allah's Messenger (may peace be upon him) as saying: Both parties in a business transaction have the right to annul it so long as they have not separated; except in transactions which have been made subject to the right of parties to annul them.

Source materials are from the University of Southern California MSA site
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