Renaming Photos People
In early use of Photos (probably as iPhotos), I mistakenly pressed "enter" with a first name when a full first-last name was offered. I thought the full name was being selected. As a result I sometimes have several versions of a single named person. I've done a ragtag job of combining these profiles, but have one troublesome name. My son-in-law displays as "Greg" in his main profile. Searching for him by last name displays him correctly with his key photo, but double-clicking him brings up the full set of photos (and faces) which are simply labeled, "Greg". I have added his last name in all the ways suggested by other questioners and often gotten the intermediate message the name has been changed. But it has not. My photos are on iCloud; does that make a difference?
MacBook Pro 13″, macOS 11.2