I have had issues in the past where upgrades are lost when a ticket is reissued. For example: Let's say I have a trip to the EU where my outbound upgrade cleared with GPU. Then I need to change the return trip to depart from a different airport. Itinerary and ticket need to change, add/collect paid, etc. Ticket reissued. When this has happened, I would often lose the outbound upgrade. Granted this was on the old UA Apollo System. And in this situation I made a change in routing. Old UA would have to do some clever gymnasitcs to get UA upgrades to stick, and I think you were SOL on Star Alliance upgrades.

I'm not sure how new UA with SHARES works with this. My concern is it seems like the ticket needs to be reissued if the GPU clears. I hope this isnt the case and it only needs to be re-synced with the original ticket. I just don't want to lose my Star Alliance upgrade on LH.

Although...now that I think of it LH is pretty good in keeping folks upgraded even if flights are cancelled, etc. I was once traveling on LH in upgraded business. My flight was cancelled due to weather and I got booked on a completely different flight. They kept me in business. On UA, in my experience, you lose your upgrade if your original flight is cancelled and you have to be rebooked on an alternate UA flight.

Thanks,