What are some examples where a big change/addition to the cast or storyline saved a show or gave a dying show a new life?

What are some examples where a big change/addition to the cast or storyline saved a show or gave a dying show a new life?

I guess the classic example is Happy Days, ABC was going to cancel the series, Garry Marshal pitched the series to ABC with Fonzie taking over as the lead character, ABC gave him the OK and the rest as they say is history.

Newhart, the underperforming comedy was retooled for season 3 and the show took off.

Not a comedy but I'll throw it in as an extra, Mannix, in the first season the show was about a fish out of water investigator working for a very structured ultramodern investigation company, to season 2, Mannix is now an independent PI with a loyal secretary Peggy.

Similar to Happy Day, Family Matters probably lasted longer if not too long when the Steve Urkel character became more of the focus to the show.

Maybe the same could be said for Good Times and J.J. Evans.

Would Lost in Space fit this conversation? The focus seemed to have changed with more comical themes with Dr. Smith as the focus in those situations.

Facts of Life- trimming away the plethora of girls to a core set of 4. Expanding the role of Mrs. Garrett as dietician and diminishing the role of the headmaster/principal.

Retooling Saved by the Bell. Moves away from teacher perspective (Miss Bliss) and shifts focuses to teenagers.

I realize that some fans of The Jeffersons strongly dislike the direction the show went, but George really needed to become friendlier with Helen's husband Tom. Having George pal around with Tom in his scheming extended the show by several seasons.

I realize that some fans of The Jeffersons strongly dislike the direction the show went, but George really needed to become friendlier with Helen's husband Tom. Having George pal around with George in his scheming extended the show by several seasons. i am one who liked the later jeffersons eps better

10 Perfect Casting Decisions That Saved Declining TV Shows (https://screenrant.com/tv-shows-best-casting-decisions-new-characters-saved/)

Sometimes when a show is struggling to get its ratings up or engage with its audience, all it needs is a new actor to shake things up in the series.

I realize that some fans of The Jeffersons strongly dislike the direction the show went, but George really needed to become friendlier with Helen's husband Tom. Having George pal around with George in his scheming extended the show by several seasons.

They did this on "The Neighborhood" too.

The Lynda Carter Wonder Woman series moved their era from WW II to a modern day govt recon show. I'm not sure it made the show better with the forsaken fashions of the 1970s, but the show was renewed for a third season which may not have happened without the time jump.

8 TV Shows That Abandoned Their Original Premise & Were Better For It (https://screenrant.com/tv-shows-abandoned-original-premise-better/)

TV shows risk everything by ditching their original premises. It often ends poorly, but sometimes new ideas are just what a show needs to stay fresh.