Not sure if this has been done before. Has to be a significant new lineup change, not just a new bassist/drummer (sorry bassists and drummers!). Really looking for ones where the band sound and identity was rebooted and maybe even had a new creative force. First examples I thought of: Fleetwood Mac 1975, bringing in Buckingham and Nicks Deep Purple In Rock, bringing in Gillan and Glover. Doesn't have to be two new members like my examples; could be one but has to be a significant change that gave the first album they did a feel of it being a 'debut'.
Fairport Convention - Expletive Delighted Brought in Rik Sanders (although depending on source, was apparently a "guest" on the previous album - although I always considered him a full time member) and Maart Allcock
Good choices with Fleetwood Mac and Deep Purple. My picks off the top of my head: Deep Purple - Burn (Coverdale and Hughes replacing Gillan and Glover) Motley Crue - self titled 6th album (John Corabi replacing Vince Neil) Suede - Coming Up (Bernard Butler replaced by Richard Oakes and gain keyboard player Neil Codling) All the above are significant due to departed and/or new members being contributing songwriters.
Only one change in the lineup but I'd go for Heaven and Hell by Black Sabbath. It was a complete reboot.
Allman Brothers Band- Seven Turns (1990) The ABB 90s comeback album with new members Warren Haynes, Allen Woody and Johnny Neel. The band broke up in the early 1980s and this record proved that the band was back.
King Crimson - Discipline Only Fripp and Bruford remained from Red. Adding Levin and Belew. Their overall sound changed quite a bit (no, they didn't become a New Wave band), while still retaining their progressiveness*. *their complexity and musicianship remained, it was just focused in a different direction.