Originally Posted by
mplsjefe
May I book the second separate leg via DL.com from ICN or do I need to use KE?
You're asking if you can book ICN-XXX on dl.com, without telling us where XXX is... No idea, but it seems like a very simple experiment. Open dl.com, type ICN as the origin, type the mystery code as the destination, enter your dates and see what happens. As noted above, you definitely cannot combine the tickets after booking them separately.