It occurred to me after seeing Ian's post, that several of Dr. MacKenzie's best courses were actually renovations, and quite drastic ones at that.
Lahinch was a renovation, he only kept a few holes.
Royal Melbourne was a renovation -- nearly every hole was rerouted, although some of the previous green sites or fairway corrdiors were kept.
Kingston Heath was a renovation -- essentially a rebunkering.
Crystal Downs was a renovation -- there was an original nine-hole course, though he only used one green site from it.