More importantly, could he possibley do "repairs" on a pre-existing silver crest badge? Mine has a slight mis-spelling of the Gaelic motto that has always been an irritation.
I'm going to guess that this would be difficult to "repair", as you'd pretty much have to redo the piece.

It's POSSIBLE to do this without completely recreating the piece from scratch: if you want the process detailed, I can.

There would also be a possibility of trying to remove the text, and solder in replacement text. But that would be VERY tricky...