"The Messenger of Allah said: 'The two parties to a transaction both have the choice so long as they have not separated or they have chosen to conclude the transaction.' Or perhaps Nafi said: "Or one of them has said to the other: 'Decide! (Sahih )
قَالَ رَسُولُ اللَّهِ ﷺ الْبَيِّعَانِ بِالْخِيَارِ حَتَّى يَفْتَرِقَا أَوْ يَكُونَ بَيْعَ خِيَارٍ وَرُبَّمَا قَالَ نَافِعٌ أَوْ يَقُولَ أَحَدُهُمَا لِلآخَرِ اخْتَرْ