It is narrated from Sayyiduna Imran bin Husayn al-Khuza'i (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "Whoever among you swears an oath about something, then sees something else better than it, let him do that which is better and make expiation for his oath."
Imam al-Tabarani (may Allah have mercy on him) said: "This hadith is not narrated from Sayyiduna Imran bin Husayn (may Allah be pleased with him) except with this chain; Sa'id bin Zarbi is alone in narrating it."
Hadith Referenceالمعجم الأوسط / باب العين / 3956
Hadith Takhrij«أخرجه ابن حبان فى «صحيحه» برقم: 4351، وابن حجر فى «المطالب العالية» برقم: 1778، والطبراني فى «الكبير» برقم: 346، 483»