I have the same question. I had it done at LGW, but a few weeks later, the tag got mangled in a baggage sorter at NRT! Anyway, do they do it at IAH? I heard a guy ask for this (a few months ago) at IAH as we were waiting for CO 10 to CDG. The concierge just laughed -- and walked away! He was full-fare J, too, because I saw his ticket as he was stowing his gear next to mine in the cabin (not that the fare should make a difference on this issue). So...I'm wondering if I can get this done at IAH.