From Sahih Bukhari (Hadith 2109):
Narrated Ibn `Umar:Allah's Messenger (ﷺ) said, "The seller and the buyer have the option of canceling or confirming the deal unless they separate, or one of them says to the other, 'Choose (i.e. decide to cancel or confirm the bargain now)." Perhaps he said, 'Or if it is an optional sale.' " Ibn `Umar, Shuraih, Ash-Shu`bi, Tawus, Ata, and Ibn Abu Mulaika agree upon this judgment
Reference: Bukhari 2109