I thought I put this thread to rest, but note the interesting examples that Sean has presented that illustrate the futility of trying to assisn designations to each architect's work on a course. I can see where that would be particularly impossible on most courses in the UK. But, that said, if at all possible, where I use either the term design or redesign, I plan to have brief descriptors of how those terms should be applied to a particular course. I don't see how redesign can stand alone, without some explanation. And, that explanation should include or imply the features remaining from the original design. As I say that, I'm reminded of one of our courses that remains problematic, in terms of classification. We know that another course existed before the Travis design was partially implemented. I have not yet found documentation about what remained of the original course, nor the identity of the original designer. But, the search for that information continues.
I would not consider using the term redesign unless there were significant changes to the routing of the original course. I would prefer that there would be enough left of the original course that demonstrates its existence. Hard for me to define how much is "enough".