Cam re-grind

I started asking RRR about it but I am still not clear so I decided to bring it over to FABO in case anyone else has the same question. He mentioned something about putting a cam lobe on, so are the lobes removable?

The cam grinder can move the center line of the lobe a little when he regrinds it... You may have gotten confused in some of the terminology when he first explained it...