Hakim b. Hazim (Allah be pleased with him) reported Allah's Messenger (ﷺ) as saying: Both parties in a business transaction have the right to annul it so long as they have not separated; and if they speak the truth and make everything clear they will be blessed in their transaction; but if they tell a lie and conceal anything the blessing on their transaction will be blotted out.
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، حَدَّثَنَا يَحْيَى بْنُ سَعِيدٍ، عَنْ شُعْبَةَ، ح وَحَدَّثَنَا عَمْرُو بْنُ، عَلِيٍّ حَدَّثَنَا يَحْيَى بْنُ سَعِيدٍ، وَعَبْدُ الرَّحْمَنِ بْنُ مَهْدِيٍّ، قَالاَ حَدَّثَنَا شُعْبَةُ، عَنْ قَتَادَةَ، عَنْ أَبِي الْخَلِيلِ، عَنْ عَبْدِ اللَّهِ بْنِ الْحَارِثِ، عَنْ حَكِيمِ بْنِ حِزَامٍ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " الْبَيِّعَانِ بِالْخِيَارِ مَا لَمْ يَتَفَرَّقَا فَإِنْ صَدَقَا وَبَيَّنَا بُورِكَ لَهُمَا فِي بَيْعِهِمَا وَإِنْ كَذَبَا وَكَتَمَا مُحِقَتْ بَرَكَةُ بَيْعِهِمَا " .
sunnah.com