The very last episode (https://decider.com/2015/05/28/one-day-at-a-time-series-finale/) of ODAAT (https://www.fame10.com/entertainment/8-things-you-didnt-know-about-the-original-one-day-at-a-time-series/?streamview=all), "Another Man's Shoes" was actually intended to be a backdoor pilot (https://www.metv.com/lists/7-potential-spinoffs-that-never-saw-the-light-of-day) for a proposed spin-off (http://mentalfloss.com/article/29964/11-ill-conceived-tv-spinoffs-almost-happened) about (https://books.google.com/books?id=XxTx1xK-q14C&pg=PA14&lpg=PA14&dq=one+day+at+a+time+another+man%27s+shoes+final+episode&source=bl&ots=ShACo8Mi95&sig=qInj1YoaqOejM1cvY67fRlLLLCY&hl=en&sa=X&ved=2ahUKEwj8k-aah4XdAhUIyoMKHbIvCjg4ChDoATAJegQIARAB#v=onepage&q=one%20day%20at%20a%20time%20another%20man's%20shoes%20final%20episode&f=false) Schneider relocating to Florida to take care of his recently deceased brother's son and daughter.

Apparently, the proposed spin-off (http://www.sitcomsonline.com/boards/showthread.php?t=339186) came to be because Bonnie Franklin wanted out of ODAAT after Season 9. She didn't like that the focus had switched to Barbara, Max, Mark and Katherine. Had there been a tenth season, then the likely plan would've been to refocus the show to Ann's apartment again. They would've probably cut Max/Michael Lembeck and Katherine/Nanette Fabray loose, and Mark/Boyd Gaines would've become recurring.

CBS wasn't ready to cut ODAAT loose as it was still in the top 20 after nine years (and I guess that CBS didn't have much else going for them sitcom-wise in 1984-85). When Bonnie Franklin turned down CBS' offer for more money (about four times what they were making before) to return (and in the process, depriving Pat Harrington, Jr. of his retirement money), they tried a backdoor pilot that had Schneider hanging around carnival folk.