Fresh Prince of Bel-Aire
Aunt Vivian is one of the most famous recasts in television history, partially because everyone noticed immediately. The first Aunt Viv, played by Janet Hubert-Whitten, had a big fight with protagonist Will Smith and said "I will never do anything with an assh*le like Will Smith." No surprise that she was then recast. Daphne Maxwell Reid replaced her for the remaining seasons.