From Sahih Bukhari (Hadith 2107):
Narrated Ibn `Umar:The Prophet (ﷺ) said, "The buyer and the seller have the option to cancel or confirm the bargain before they separate from each other or if the sale is optional." Nafi` said, "Ibn `Umar used to separate quickly from the seller if he had bought a thing which he liked
Reference: Bukhari 2107