Team Foundation Server - is there a way to make a changeset into a candidate for merging again

Question

I was recently using the following command in Visual Studio 2012 developer command prompt to clear out changesets that weren't ever to be merged between our mainline and production branches (things like local config file check-ins)

tf merge /discard /version:C12345~C12346 $/MainLine/Content $/Production /recursive

Unfortunately, in the process of doing this I have removed a couple of candidate changesets that do actually still require to be merged from our mainline branch to our production branch. My bad, but before I go down the route of having to manually make these changes in production branch I wanted to ask if there is a way to make a changeset in our mainline branch into a candidate for merging up to our production branch again after i have previously merge-discarded it?

I've been able to find plenty of info on the web about merge/discards but not on reversing this....so any pointers in the direction of help would be appreciated (if what I am asking for is even achievable).

Update

Ok, so we have been performing the merge from our source to target branch today, and I just wanted to say thanks to James for his answer. This worked a treat on the changesets that were no longer showing as candidates using the merge wizard within TFS.

Answer 1

use /version:c1234 /force

e.g.

tf merge /force /version:C12345~C12346 $/MainLine/Content $/Production /recursive