أَخْبَرَنَا زِيَادُ بْنُ أَيُّوبَ، قَالَ حَدَّثَنَا هُشَيْمٌ، قَالَ أَنْبَأَنَا مَنْصُورٌ، وَيُونُسُ، عَنِ الْحَسَنِ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ سَمُرَةَ، قَالَ قَالَ لِي النَّبِيُّ صلى الله عليه وسلم ‏"‏ إِذَا آلَيْتَ عَلَى يَمِينٍ فَرَأَيْتَ غَيْرَهَا خَيْرًا مِنْهَا فَأْتِ الَّذِي هُوَ خَيْرٌ وَكَفِّرْ عَنْ يَمِينِكَ ‏"‏ ‏.‏

It was narrated that 'Abdur-Rahman bin Samurah said: "The Prophet said to me: 'If you swear an oath, and you see something that is better, then do that which is better and offer expiation for your oath.'" Translation Not Available

Book Ref: Sunan An Nisai Book 35 Hadith 3789
Web Ref:  Sunan An Nisai Vol 4 Book 35 Hadith 3820