The Messenger of Allah ﷺ as saying: Each one of the two parties in a business has an option (to annul it) against the other party so long as they have not separated, except in a conditional bargain.  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ الْمُتَبَايِعَانِ كُلُّ وَاحِدٍ مِنْهُمَا بِالْخِيَارِ عَلَى صَاحِبِهِ مَا لَمْ يَفْتَرِقَا إِلاَّ بَيْعَ الْخِيَارِ  

"Or one of them tells the other: "Exercise the right."  

عَنِ النَّبِيِّ ﷺ بِمَعْنَاهُ قَالَ أَوْ يَقُولُ أَحَدُهُمَا لِصَاحِبِهِ اخْتَرْ  

The Prophet ﷺ said: Both parties in a business transaction have a right to annul it so long as they have not separated unless it is a bargain with the option to annul is attached to it; and it is not permissible for one of them to separate from the other for fear that one may demand that the bargain be rescinded.  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ الْمُتَبَايِعَانِ بِالْخِيَارِ مَا لَمْ يَفْتَرِقَا إِلاَّ أَنْ تَكُونَ صَفْقَةَ خِيَارٍ وَلاَ يَحِلُّ لَهُ أَنْ يُفَارِقَ صَاحِبَهُ خَشْيَةَ أَنْ يَسْتَقِيلَهُ  

We fought one of our battle, and encamped at a certain place. One of our companions sold a horse for a slave. After that they remained there for the rest of day and night. When the next morning came, they prepared themselves for departure. The buyer of the horse began to saddle it, but the seller was ashamed (of the transaction). He went to the man (buyer) and asked him to annul the transaction. The man refused to hand it over (the horse) to him. He said: AbuBarzah, the companion of the Prophet ﷺ, is to decide between me and you. They went to AbuBarzah in the corner of the army. They related this story to him. He said: Do you agree that I make a decision between you on the basis of the decision of the Messenger of Allah ﷺ? The Messenger of Allah ﷺ said: Both parties in a business transaction have an option (right) to annul it so long as they have not separated. Hisham to Hassan said that Jamil said in his version: "I do not think that you separated."  

غَزَوْنَا غَزْوَةً لَنَا فَنَزَلْنَا مَنْزِلاً فَبَاعَ صَاحِبٌ لَنَا فَرَسًا بِغُلاَمٍ ثُمَّ أَقَامَا بَقِيَّةَ يَوْمِهِمَا وَلَيْلَتِهِمَا فَلَمَّا أَصْبَحَا مِنَ الْغَدِ حَضَرَ الرَّحِيلُ فَقَامَ إِلَى فَرَسِهِ يُسْرِجُهُ فَنَدِمَ فَأَتَى الرَّجُلَ وَأَخَذَهُ بِالْبَيْعِ فَأَبَى الرَّجُلُ أَنْ يَدْفَعَهُ إِلَيْهِ فَقَالَ بَيْنِي وَبَيْنَكَ أَبُو بَرْزَةَ صَاحِبُ النَّبِيِّ ﷺ فَأَتَيَا أَبَا بَرْزَةَ فِي نَاحِيَةِ الْعَسْكَرِ فَقَالاَ لَهُ هَذِهِ الْقِصَّةَ فَقَالَ أَتَرْضَيَانِ أَنْ أَقْضِيَ بَيْنَكُمَا بِقَضَاءِ رَسُولِ اللَّهِ ﷺ قَالَ رَسُولُ اللَّهِ ﷺ الْبَيِّعَانِ بِالْخِيَارِ مَا لَمْ يَتَفَرَّقَا قَالَ هِشَامُ بْنُ حَسَّانَ حَدَّثَ جَمِيلٌ أَنَّهُ قَالَ مَا أُرَاكُمَا افْتَرَقْتُمَا  

When Abu Zur'ah made a business transaction with a man, he gave him the right of option. He then would tell him: Give me the right of option (to annul the bargain). He said: I heard AbuHurayrah say: The Messenger of Allah ﷺ said: Two people must separate only by mutual consent.  

كَانَ أَبُو زُرْعَةَ إِذَا بَايَعَ رَجُلاً خَيَّرَهُ قَالَ ثُمَّ يَقُولُ خَيِّرْنِي وَيَقُولُ سَمِعْتُ أَبَا هُرَيْرَةَ يَقُولُ قَالَ رَسُولُ اللَّهِ ﷺ لاَ يَفْتَرِقَنَّ اثْنَانِ إِلاَّ عَنْ تَرَاضٍ  

The Messenger of Allah ﷺ as saying: Both parties in a business transaction have a right of option (to annul it) so long as they are not separated ; and if they tell the truth and make everything clear, they will be blessed in their transaction, but it they conceal anything and lie, the blessing on their transaction will be blotted out. Abu Dawud said: A similar tradition has also been transmitted by Sa'id b. Abi 'Arubah and Hammad. As regards with Hammam, he said in his version: Until they separate or exercise the right of option (to annul the transaction), saying the words of option three times.  

أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ الْبَيِّعَانِ بِالْخِيَارِ مَا لَمْ يَفْتَرِقَا فَإِنْ صَدَقَا وَبَيَّنَا بُورِكَ لَهُمَا فِي بَيْعِهِمَا وَإِنْ كَتَمَا وَكَذَبَا مُحِقَتِ الْبَرَكَةُ مِنْ بَيْعِهِمَا