The episode "The Girls School" (episode #1.24) was the pilot for the spin-off The Facts of Life (1979).
As is the case with many pilots, there were a number of differences between the episode and what would come to be The Facts Of Life. Among them, the exterior establishing shot and interior set of the Dormatory were completely different; The school was called Eastlake, not Eastland; Featured a never again seen Headmaster named Mr Crocker, as opposed to Mr Bradley; Jennifer and Laura didn't become characters on the series, and Natalie and Cindy did not appear here.
Although in this episode, the girls' academy is called "Eastlake", when the spin-off The Facts of Life (1979) premiered later that fall, which was set at the school, the name of the academy was changed to "Eastland."