In that sure, they don't out and out pretend that the first season (https://forums.primetimer.com/topic/5450-before-the-retooling-nancy-molly-cindy-sue-ann-mr-bradley-and-miss-mahoney/) didn't exist (https://reelrundown.com/tv/Whatever-Happened-to-the-Cast-of-The-Facts-of-Life), but it could otherwise, still be looked at (https://www.manic-expression.com/2014/01/25/a-look-at-tv-shows-which-changed-premise-for-better-and-for-worst-3/) as inconsequential (http://www.tellytalk.net/threads/the-facts-of-life.11580/post-304522).

Season 2 was definitely a soft reboot: a new set, a halfway different cast, new theme music, new writers, and even a different soundstage. However, there were still guest appearances from the old cast, some writer crossover, and the setting and star remained the same. The changes were less severe than series like Charles in Charge, but more drastic than many other shows.

However, there are nice moments of continuity between Seasons 1 and later: we see the Lost Girls on occasion; Tootie's roller skates are still visible; the Eastland uniforms remain unchanged; and the format of the show (young girls go to Mrs. Garrett for advice) remains basically the same.

They are often considered by many people as two different shows but I think retool is the right word. As Retro said there are several continuity moments

Yep they changed a lot of elements but kept a lot too. S5 was a pretty big change as well, they only didn’t remove 5 cast members

The new producers from my understanding, were going for more realism and message based episodes. They already knew they were bringing in a poor girl (Jo) on scholarship so what better source of conflict than to pair her against the one character (Blair) who came from obscene wealth.

And then Tootie had potential for ethnic based stories while Natalie for "real" girl realness. So all in all, they chose whom they chose due to potential storytelling and character development.

The new producers from my understanding, were going for more realism and message based episodes. They already knew they were bringing in a poor girl (Jo) on scholarship so what better source of conflict than to pair her against the one character (Blair) who came from obscene wealth.

And then Tootie had potential for ethnic based stories while Natalie for "real" girl realness. So all in all, they chose whom they chose due to potential storytelling and character development.

The new producers came from One Day at a Time, a show with a small cast. They didn't know how to work with a large cast and no experience with a large cast. The four original girls were going to be Blair, Natalie, Tootie, and Molly. The idea of Jo came from them watching Little Darlings.