This may be of some use to people combining VS and DL flights.

I booked A-B-C, where A-B is VS metal, and B-C is Delta. All booked as one itinerary, via the VS site, in M class so I could upgrade the VS legs to PE.

I called today, and was initially told that I couldn't upgrade, because the VS legs were married to DL flights. The two options initially given were :-

1.) "unmarry" the flights, which somehow would up the ticket price by £700 (but allow me to upgrade), or

2.) Cancel the whole thing (without cost.)

I said to go with 2.), as I could fly US for the same price and upgrade with them.

The agent, on hearing this, did an about-face, and said they would 'unmarry' the flights for the same price as before, and process the upgrades.

When I look the flights up (they show on both the VS and DL sites) they seem to remain happily married

Did I just get a bad agent, or is it really this tricky to sort out an upgrade?