Kicking this thread back in gear...

Tried to use miles to upgrade two LH metal flights from paid biz to first. My first leg was in Paid C on a UA codeshare. I was informed that I could only use my miles if the flight had an LH number. Seems odd since they're UA miles.

The return in on D class on an LH number. In this case, it was the D fare that killed me.

My corporate travel agent booked the flights and trying to change them is near impossible, so I think will just go the SWU route instead...