Hello! I am looking to fly SAN - SEA - ICN - SIN in a few months. I see that I can buy this all on Delta with the ICN - SIN segment on Korean Air metal (But a DL flight number). When I called in to have a GUC applied to the segments I was informed:

1) There is no upgrade options for the Korean Air segment with a GUC. Is that really correct?

2) That I have to purchase this through Delta but then CALL KE and give them additional money for a "seat" on the ICN - SIN segment. Any seat. Not just upgrade.

I had the agent check twice and she said that Yes, even though I am paying Delta for the ICN - SIN segment that I don't actually get a physical seat. That I have to call Korean and pay additional for an actual seat. I asked how much she said "no way to tell".

This is very confusing and I am assuming she is incorrect.

Help!