The Book of Oaths
وَحَدَّثَنَا عُبَيْدُ اللَّهِ بْنُ مُعَاذٍ، حَدَّثَنَا أَبِي، حَدَّثَنَا شُعْبَةُ، عَنْ عَبْدِ الْعَزِيزِ بْنِ رُفَيْعٍ، عَنْ تَمِيمِ بْنِ طَرَفَةَ، عَنْ عَدِيِّ بْنِ حَاتِمٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " مَنْ حَلَفَ عَلَى يَمِينٍ فَرَأَى غَيْرَهَا خَيْرًا مِنْهَا فَلْيَأْتِ الَّذِي هُوَ خَيْرٌ وَلْيَتْرُكْ يَمِينَهُ " .Adi b. Hatim reported Allah's Messenger (ﷺ) as saying:He who took an oath, but he found something else better than that, should do that which is better and break his oath
From Sahih Muslim, whose reports the scholars accept as authentic.