I think that, as other have stated, if you teach a "dressage change" you can easily get a "hunter change" on that horse by virtue of not collecting the canter. That is, IF your horse is totally relaxed about changes and doesn't get one iota tense.
My 3rd/4th level horse has never been a hunter a day in her life. But, when I tried her prior to purchasing her, I essentially got a hunter change on her simply because I did not have the canter collected enough. (My 2nd time riding her and I just wanted to make sure the changes were confirmed enough that I could get them.) Matter of fact, the trainer's words were "yes, she changed but it was really flat."
And another horse I bred and raised has been a dressage horse and we have been working on changes, teaching them the "dressage way." I have been taking her for some jumping lessons with a hunter trainer for fun (another one of my mares is in hunter training because that is what she is best suited for.) The other day we did a change while jumping and the hunter trainer commented on what a great change it was. Again, canter had no collection so change was flat and smooth.