Ibn 'Umar (Allah be pleased with them) reported Allah's Messenger (sallallaahu alayhi wa sallam) as saying:
Both parties in a business transaction have the right to annul it so long as they have not separated; except in transactions which have been made subject to the right of parties to annul them.
[Sahih al-Bukhaari and Sahih Muslim]
Imaam al-Nawawi said: This hadiith is evidence to khiyaar al-majlis for both parties involved in a transaction after the sale has been contracted as long as they do not physically separate from the majlis.
This is the opinion of the majority of scholars from among the Companions and the Taabi'uun and those who followed them. Those who held this opinion include:
Ali bin Abi Taalib
Abu Barzah al-'aslamii
Sa'iid bin al-musayyib
Ibn Abi Dhi'b
Sufyaan bin 'uyainah
Ali bin al-madini
Ahmad bin Hanbal
'ishaaq bin rahwaih
All of the scholars of hadith
Maalik and Abu Hanifah said khiyaar al-majlis is not established.
Who knows the Religion better than the Companions (may Allaah be pleased with them) of the Messenger of Allaah (sallallaahu alayuhi wa sallam)?
Volume 6 Page 223