I've been trying to buy (please note BUY - not award / upgrade) first class connections on Emirates when flying through DBX in J on UA, but have never seen F connections offered as an option on the search results. Even when trying other strats like splitting fares, splitting into separate tickets or using google and trying to select UA as the booking engine (it's never offered when F connections are chosen) I can't get a mixed J/F itinerary. I booked a J ticket and called Global Services asking to help me upgrade the EK segments, but after they spoke to the rate desk they said they couldn't sell me an upgrade because their system no longer had F international - so their system wouldn't price it. Emirates confirmed the inventory was available, but UA just couldn't sell it to me.

I've heard from others that you can buy F class connections on LH, and they even showed a receipt (I didn't see pricing, but I did see the 016 ticket stock number), but for the life of me I can't replicate that itinerary option either using the UA app or website. The itinerary was in November of this year, so it's still far in the future and very searchable. No matter how I frame the search it only shows business class connections on LH - even when you expand the listing to see fare buckets.

This begs the general question - can anyone reliably / easily see F connections on partner airlines when they search the UA website or app? If so, how?

Thanks for any help!