Thanks for looking into it. I tried. The agent took forever and tried consulting her colleagues only to say that she couldn't see it. I didn't have the time (the first call took about 40 mins) to hang up and call again.
I'm also actively looking for other award options on 12/21 or a day in each direction.
Thanks again for your help.
So sorry about that, it's a pain when it happens. United and Expertflyer can see it, so it's most likely there. Were they trying to rebook the whole ORD-LIS-ORY, or just LIS-ORY? ORD-LIS is certainly not there (so that one should
not be changed), that's for sure, but there are plenty of LIS-ORY options (you could take a later flight and explore Lisbon, it's lovely!), or even LIS-OPO-ORY.
Otherwise, and I know it's not ideal, there is availability on Swiss at 2:25 pm on Dec 22, via ZRH to CDG (LX2085 connecting to LX644).