Hannitty Coombes became just Hannitty when Alan Coombes left.
The Norm Show starring Norm McDonald became just Norm
What’s Happening! brought back key cast members a few years later for Whats Happening Now!!
Not sure if this counts but every year on its title sequence, Gotham adds a different sub-title, for instance season 2 IIRC was Gotham: Rise of the Villains, and this year its Gotham: Mad City
Spencer (with Chad Lowe in the title role) became Under One Roof (with Lowe replaced by another actor, and the focus became less on Spencer and more on the people around him).
Tattinger’s became Nick & Hillary, but that one gets an asterisk as the first was an hour-long drama and the second a half-hour sitcom.
Do shows that had character removals (so they’re more spinoff/sequel series, a la Archie Bunker’s Place) count? If so, there are some others: Together We Stand became Nothing is Easy when the “father figure” left the show Second Chance (a dead man comes back as an angel figure to straighten out his own life when he was a teenager) got rid of the “angel” character and became Boys Will Be Boys Duet became Open House; IIRC, the main male character left the show in the switch
Quite a few British shows aired in different countries under different names. Patrick McGoohan’s 1960s Danger Man aired as Secret Agent in the USA and Destination Danger and John Drake in other English-speaking countries. But kept Danger Man in Canada.
Randall and Hopkirk (Deceased) became My Partner, the Ghost in the US; The Good Life became The Good Neighbors; and I’ve heard that the show aired in the US as Are You Being Served? was originally titled Grace and Favor in the UK, though I recently met a Brit who told me that isn’t so, he’s always known it as Are You Being Served? (I wondered if he was pulling my leg.)
The short-lived American program Nobody’s Perfect was renamed from Hart in San Francisco to avoid confusion with Hart to Hart, which debuted around the same time. Curiously, it was rerun in the UK as Hart of the Yard, because there was an existing sitcom called Nobody’s Perfect.
Too Close For Comfort was renamed to The Ted Knight Show when the two daughters left the show, but it was named back again when the episodes were packaged for syndication.
I would argue it was more of a spinoff, with most of the same characters. Since the “minister” was now PM, the plot lines had to be correspondingly different.
If one allows spinoffs and sequels as name changes, then the excellent British miniseries “House of Cards” transmuted into “To Play the King” and “The Final Cut” – all fantastic television, BTW, which for some reason I prefer to the Netflix adaptation.
Here’s a twist: a TV show that didn’t change its name, but changed its theme. From what I’ve seen of the early “Father Knows Best”, throughout more or less the first season the title was meant to be ironic, as father basically didn’t seem to know a damn thing and made judgments that turned out to be foolish. It was only beginning around the second season that father suddenly became a man of faultless wisdom and the title acquired a literal meaning, and the thing turned into a kind of morality play and glorification of the idealized 1950s American family.
The lines between “new series” and “new name” sometimes get blurred, particularly in retrospect when the DVD releases re-join the differently named shows back under the same umbrella. For instance, the Batman: The Animated Series DVD set combines Batman: The Animated Series, The Adventures of Batman and Robin (re-tooled to feature team stories rather than mostly solo Batman stories), and The New Batman Adventures (art style reworked and setting time-skipped a few years forward, with Tim Drake as Robin, Dick Grayson as Nightwing, and Batgirl appearing much more frequently).
Just Good Neighbors, without the article. I believe they had to change the name on that one because there had been another series called The Good Life on US TV several years earlier. It starred Larry Hagman, Donna Mills, and David Wayne, all of whom went on to work in Dallas.
It’s a Living, primarily known for Anne Jillian, was renamed Making A Living after its first season and then became It’s A Living when it went into first-run syndication. :dubious: