This is the upper edge of the front bodice. I did the same thing with the back bodice
I have made a 1/2" fold across the neck facing and pinned it with the yellow ball headed pin. Then when I laid it on my already cut out neck facing there was 1/2" of extra fabric to trim off. Sometimes an alteration like this can change the shape of a facing so much that a whole new piece needs to be cut, but I was lucky this time. But, I did pin in the front a little, I hope I don't have to change the neck facing anymore.