ENOfficial
It was narrated from Samurah that the Messenger of Allah (ﷺ) said: "The two parties to a transaction have the choice (of annulling it) so long as they have not yet parted. "
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا مُحَمَّدُ بْنُ يَحْيَى، وَإِسْحَاقُ بْنُ مَنْصُورٍ، قَالاَ حَدَّثَنَا عَبْدُ الصَّمَدِ، حَدَّثَنَا شُعْبَةُ، عَنْ قَتَادَةَ، عَنِ الْحَسَنِ، عَنْ سَمُرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " الْبَيِّعَانِ بِالْخِيَارِ مَا لَمْ يَتَفَرَّقَا " .
sunnah.com