I am having the devil of a time getting the UA website to offer the CDG-SFO nonstop as an option.

My spouse is currently in Paris, having flown to London first. Her original booking was PDX-ORD-CDG, but due to concerns about weather, I coughed up the $200 and rebooked her PDX-SFO-CDG, which I could only do by calling in, and involved her giving up her upgrade to Business (which worked out OK because the flight was nearly empty, she got a whole row in E-).

Now she wants to push back her return a few days, and while I can see the flight if I try to book a non-stop one-way, there is absolutely no way I can make it come up (in the "change flight" section) as a routing of CDG-PDX, and I cannot even get it to come up if I ask to change her flight to CDG-SFO and check the non-stop box! It routes through IAD, ORD, IAH, or even EWR, but will not show the non-stop.

I will get around this by calling in, but can anyone venture any ideas on why United doesn't want to sell the CDG-SFO route? It's practically empty in Economy.