Sunan an-Nasa'i, Hadith 3790 ⓘ
'Abdur-Rahman bin Samurah said: "The Messenger of Allah said: 'If you swear an oath, then you see something that is better, then do that which is better and offer expiation for your oath.'"
أَخْبَرَنَا عَمْرُو بْنُ عَلِيٍّ، قَالَ حَدَّثَنَا يَحْيَى، قَالَ حَدَّثَنَا ابْنُ عَوْنٍ، عَنِ الْحَسَنِ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ سَمُرَةَ، قَالَ قَالَ يَعْنِي رَسُولَ اللَّهِ صلى الله عليه وسلم " إِذَا حَلَفْتَ عَلَى يَمِينٍ فَرَأَيْتَ غَيْرَهَا خَيْرًا مِنْهَا فَأْتِ الَّذِي هُوَ خَيْرٌ مِنْهَا وَكَفِّرْ عَنْ يَمِينِكَ " .
also referenced under: Book 35, Hadith 30 (In-Book) & Volume 4, Book 35, Hadith 3821 (DarusSalam)