Shows That Replaced Notable Characters With Other Performers

There's the example of Fresh Prince of Bel Air with Vivian, played by Janet Hubert replaced by Daphne Reid. I wish that I watched more classic TV so that I could give a better answer.

On Hogan's Heroes, Ivan Dixon played Sgt. James Kinchloe for five seasons. For the sixth and final season, Kenneth Washington replaced Dixon. Although technically not the same character, Washington's Sergeant Richard Baker assumed all of Kinchloe's duties on the show.

Ivan Dixon



Kenneth Washington

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The original Star Trek was cancelled in 1969. In 1973 it was resurrected as an animated series for what was essentially a fourth season. However, there's wasn't enough money in the budget to bring back Walter Koenig who played Chekov in Seasons 2 and 3.

To save money, as well as to show off more alien characters, Chekov was replaced as navigator by Lt. Arex, voiced by James "Scotty" Doohan. Doohan reportedly voiced 34 different characters on the animated series.

Walter Koenig



James Doohan

On the "George Burns and Gracie Allen Show," [1950-1958], their neighbor, Blanche Morton (Bea Benaderet), was married to 4 Harry Mortons.

- John Brown ... 7 episodes

- Hal March ... 15 episodes

- Fred Clark ... 75 episodes

- Larry Keating ... 199 episodes

The introduction of Larry Keating was a classic moment:

On Dallas, Donna Reed replaced Barbara Bel Geddes as Miss Ellie for a season and was replaced herself when Bel Geddes came back.

sounds similar to the Becky role swapping on Roseanne (mentioned earlier  ) 

The story I heard was that Bel Geddes held out for more money one year and was replaced by Reed, but then came to a new contract agreement and came back to the show.

Over on Facebook there is an interesting gallery of all the actors who played recurring character Jonathan Kaye on the original Hawaii Five-O TV series:

The Many Faces of Jonathan Kaye | Facebook

For the record, my favorite Kayes are:

#1. Joseph Sirola



#2. Tim O'Connor



#3. Bill Edwards

Dr Who


Actors who have played Dr Who

Changes to the cast were a regular fixture of the series - only five of the series' 26 seasons (the 8th, 9th, 22nd, 25th and 26th) did not include an arriving or departing regular cast member. Only two regular characters did not get a departure scene: the character of Dodo Chaplet disappeared halfway through the 1966 serial "The War Machines"; the character Liz Shaw simply did not return after the 1970 season. The departures were explained in dialogue in subsequent episodes. Actors Mary Tamm and Colin Baker did not get leaving scenes - their characters (Romana and the Doctor, respectively) returned at the beginning of the following season played by different actors. However, their characters belonged to a race whose appearance, it had already been established, would frequently change thus making the change of actors easy to explain.