I created a monster : reset faces in Photos

Hi all,

I got something very weird in Photos (the latest one for High Sierra and iOS11 -- iCloud photo library is activated on all devices)

1/ I think 3 faces have been merged by mistake : let's say "Eric", "Tim" merged into "John" face

2/ Only John remains but it's totally irrelevant (mixed pictures of 3 different people).

3/ I've decided to reset John : select All pictures and remove the face ("John is not in these pictures")

I got a situation where i have no more Eric, or Tim, or John

- I've then named Eric and Tim faces back in their pictures: I was considering that I would teach their faces again to Photos

--> Problem : Photo automatically merges Eric & Tim and names them John !

--> Even if -in this situation- John face did not exist from me (remove at stept3 above) but Photos renames Eric & Tim by its own to Jonh

Is there any way to reset the entire Face database : I would prefer setting everyone back instead of fighting with this AI ...

Yoann