It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "Between any two parties to a sale, the sale remains revocable until they separate, except a sale with an option (khiyar)."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13572