There are several ways they like to make movies from television shows.
There is the continuation of the story. This will include the same actors and an extension of the same story lines.
Most recently "Sex and the City".
But even back in the seventies.
"Star Trek" was a really popular reboot. One little three season movie launched a franchise.
Another way is to update the same story with modern twists.
It soon becomes something new.
Sometimes they take a serious movie and give it a comic twist.
Joe Friday was all business.
Not so much.
They also like to go the other way.
From pink pastals.
Then there is outright satire.
"The Brady Bunch"
"Starsky and Hutch"
But probably the best movie from a television show is "The Fugitive".
Of course the movie story line has benefits over a television series. When you have a television show with a character on the run, you have to continue to create obstacles to keep them running.
With a movie you can get to a resolution point and not worry about what to have in next week's show. Plus Harrison Ford and Tommy Lee Jones are awesome.