No problem. Now I'm glad I remembered it! It's not something that readily comes to mind because it's something you do, maybe, once and then don't usually have to do again.
The Send To thing is always at the front of my mind because I do it nearly every day, but Remap is really much more appropriate for this situation. Your old top-level music directory at the left, your new top-level music directory at the right, do it, and it's done.