While the remake of One Day at a Time has just been renewed for a 3rd season at Netflix, let's take a look at a pilot for the original series.
In fact, it went by a different title.
Three to Get Ready was produced for CBS in 1975. The setting remains the same, Indianapolis. Ann Romano (Bonnie Franklin), however, is a nurse being wooed by a doctor (Lewis J. Stadlen, later of Benson), barely a month after her divorce had been finalized. Also, Ann only has one daughter, Julie (Mackenzie Phillips), not two. Dwayne Schneider (Pat Harrington) is the building superintendent.
After having been turned down for a part on Maude, Marcia Rodd plays Ann's upstairs neighbor. She was cut when the changes were made to develop One Day at a Time, and would later surface on 13 Queens Boulevard, among other places.
It's easy to see why Stadlen was cut, as well.....
Stadlen, a second generation actor (dad was New York kids show personality and voice actor Allen Swift), came off as too abrasive and forward, which today would get a guy in trouble on or off the job. Since not all the familiar elements are yet in place (Julie was softened a little by the time the series started), I think you can understand why this ended up failing, and needed to be retooled.