I've talked a lot about spin-offs, when a character is introduced in one series and spun off into their own. Some however are more than spin-off's, they are continuations.
Now a lot of shows will dramatically change focus to spice things up. Empty Nest had Harry go from working in a hospital to a free clinic. Gimmee A Break changed the setting to New York City. Welcome Back, Kotter had a new teacher and focused more on the school. But in the end these were still the same shows. But what happens when the show runners want the show to continue, but one or all of the main stars or even entire cast don't want to come back? The show literally becomes its own spin-off, sometimes keeping the name we love and other times changing to reflect the change. Here are five examples:
Mayberry R.F.D
Andy Griffith was ready to move on from The Andy Griffith Show. So in the eighth season the town became more of the focus with Griffith being seen less and less. Andy Taylor moved away at the end of Andy Griffith and when the show officially becomes Mayberry R.F.D. it was literally the same show, minus Andy and Opie. Who did make appearances.