Sunan Abi Dawud — Wages (Kitab Al-Ijarah) — Hadith No: 3454
Translation
Narrated 'Abdullah bin 'Umar:The Messenger of Allah (ﷺ) as saying: Each one of the two parties in a business has an option (to annul it) against the other party so long as they have not separated, except in a conditional bargain