On the authority of his father that the Prophet ﷺ said: I swear by Allah that if Allah wills I shall swear on an oath and then consider something else to be better than it without making atonement for my oath and doing the thing that is better. Or he said (according to another version): But doing the thing that is better and making atonement for my oath.  

أَنَّ النَّبِيَّ ﷺ قَالَ إِنِّي وَاللَّهِ إِنْ شَاءَ اللَّهُ لاَ أَحْلِفُ عَلَى يَمِينٍ فَأَرَى غَيْرَهَا خَيْرًا مِنْهَا إِلاَّ كَفَّرْتُ عَنْ يَمِينِي وَأَتَيْتُ الَّذِي هُوَ خَيْرٌ أَوْ قَالَ إِلاَّ أَتَيْتُ الَّذِي هُوَ خَيْرٌ وَكَفَّرْتُ يَمِينِي  

The Prophet ﷺ said to me: 'Abd al-Rahman b. Samurah, when you swear an oath and consider something else to be better than it, do the thing that is beter and make atonement for your oath. Abu Dawud said: I heard Ahmad (b. Hanbal) permitting to make atonement before breaking the oath.  

لِيَ النَّبِيُّ ﷺ يَا عَبْدَ الرَّحْمَنِ بْنَ سَمُرَةَ إِذَا حَلَفْتَ عَلَى يَمِينٍ فَرَأَيْتَ غَيْرَهَا خَيْرًا مِنْهَا فَأْتِ الَّذِي هُوَ خَيْرٌ وَكَفِّرْ يَمِينَكَ  

"Make atonement for your oath and then do the thing that is better." Abu Dawud said: The version of this tradition transmitted by Abu Musa al-Ash'ari, 'Adi b. Hatim and Abu Hurairah are variant. Some of them indicate breaking the oath before making atonement, and other making atonement before breaking the oath.  

عَنْ يَمِينِكَ ثُمَّ ائْتِ الَّذِي هُوَ خَيْرٌ