Thank you everyone for the replies.

In answer to rens' question, I was holding, but had not yet ticketed, an RTW itinerary, so changes were free. I have now ticketed (very exciting) using the longer route, which should give me the "coveted" PLT status. As for what happens after that, I guess I'll take the suggestion of those on this board to annotate the PNR and maybe print the revised itinerary. There's only so much I can do, I suppose, if LAN won't accept it. Again, it's a bit sad that you can't apparently print a card out like I was able to do with Starwood. Anyway, thanks for the advice.