How to re-link an actual stored file to a Matched/Cloud track?

While turingtest2's comment is correct, there are some caveats as I'm finding out:

• If you're near the 100,000 track limit of Match, attempts to drag files into the library that already have Uploaded/Matches iCloud equivalents results in a warning that you've exceeded the limit size. You then have to wait a certain amount of time before you can try again with a smaller selection. How long? It varies for me from a couple of seconds to an hour or so. A week after recreating my library due to a Genius issue, I'm still trying to relink my 96,000 track library -- only 35k tracks have relinked so far. I assumed that I could only work in the "free" space, i.e. files being uploaded were considered to be new before being matched, so relinking 5000 tracks when you only have 4000 tracks left "free" would fail, but there's something else going on as frequently that limit is a lot lower.
• If the original file was Matched by an earlier version of the fingerprint mechanism and chose a slightly different version, the relink will fail and either the file will be Uploaded in parallel or flagged as a duplicate and not linked. With the latter I find selecting it and using "Add to library" again usually resolves it. With the former I just tend to delete the earlier iCloud version and go with the newer upload.
• Sometimes the duration of the iCloud and refreshed files will differ despite there being no change to the source file and then you'll end up with two duplicated Uploaded files. I'm guessing this is due to an MP3 encoding issue but I've never really figured it out.

Import your local files. Music should work out they are duplicates of the files in the cloud and start using the locally stored higher quality version.

tt2