Bulugh al-Maram #947

Narrated Ibn 'Umar (RA): Allah's Messenger (ﷺ) said: "Both parties in a business transaction have a right to annul the transaction, so long as they have not separated and remain together; or one of them gives the other the choice (to conclude or annul the transaction); so, if one of them gives the other the choice (to conclude or annul the transaction) and then they make the transaction accordingly, the transaction then becomes binding; or if they separate after having made the transaction and none of them has annulled it, the transaction then becomes binding." .