Hadith.3762 - Imam (as) said: "Whenever a man buys something from another man, they both have the option (to cancel the deal) until they part ways. Once they part, the sale becomes binding."
Man Lā Yaḥḍuruh al-Faqīh #392Hadith.4021 - Abd al-Rahman ibn al-Hajjaj asked Imam (as) about a man who buys food from another man who does not have it in his possession...