The Prophet ﷺ said, "No deal is settled and finalized unless the buyer and the seller separate, except if the deal is optional (whereby the validity of the bargain depends on the stipulations agreed upon).  

عَنِ النَّبِيِّ ﷺ قَالَ كُلُّ بَيِّعَيْنِ لاَ بَيْعَ بَيْنَهُمَا حَتَّى يَتَفَرَّقَا إِلاَّ بَيْعَ الْخِيَارِ  

The Prophet ﷺ said, "Both the buyer and the seller have the option of canceling or confirming the bargain unless they separate." The sub-narrator, Hammam said, "I found this in my book: 'Both the buyer and the seller give the option of either confirming or canceling the bargain three times, and if they speak the truth and mention the defects, then their bargain will be blessed, and if they tell lies and conceal the defects, they might gain some financial gain but they will deprive their sale of (Allah's) blessings."  

أَنَّ النَّبِيَّ ﷺ قَالَ الْبَيِّعَانِ بِالْخِيَارِ مَا لَمْ يَتَفَرَّقَا قَالَ هَمَّامٌ وَجَدْتُ فِي كِتَابِي يَخْتَارُ ثَلاَثَ مِرَارٍ فَإِنْ صَدَقَا وَبَيَّنَا بُورِكَ لَهُمَا فِي بَيْعِهِمَا وَإِنْ كَذَبَا وَكَتَمَا فَعَسَى أَنْ يَرْبَحَا رِبْحًا وَيُمْحَقَا بَرَكَةَ بَيْعِهِمَا قَالَ وَحَدَّثَنَا هَمَّامٌ حَدَّثَنَا أَبُو التَّيَّاحِ أَنَّهُ سَمِعَ عَبْدَ اللَّهِ بْنَ الْحَارِثِ يُحَدِّثُ بِهَذَا الْحَدِيثِ عَنْ حَكِيمِ بْنِ حِزَامٍ عَنِ النَّبِيِّ ﷺ