While working on on one of my jackets I ripped off the knit collar plan to put it back on after I had cut down the jacket, but I am small and collar already made was to large for my jacket, Here is my idea to make it smaller cut off the end on each side and to keep it from raveling added some very narrow bias tape ( this can be contrasting or matching in color) tuck under the outside edge the outer end will cough in the neck seam. I hope this is helpful to someone.