I got my first Ulti-downgrade today, but it was my choice, so all is good
a quick report regarding same-day changes as Ulti: I was booked on the evening WAW-CDG-ZRH in J. I arrived this morning in WAW from KBP (by train) and since all went smoothly and on time I managed to get to Chopin airport shortly before 11 to catch the earlier HOP flight at 12:20, connecting to the earlier ZRH-flight. The E90 on WAW-CDG had still 3 free seats in J, however the A321 to ZRH was fully booked in J and had only a few seats left in Eco. I called the hotline and requested a same-day change which was denied given lack of availability on the CDG-ZRH leg. I offered to take this leg in Y, but wanted to keep the longer leg WAW-CDG in J, at least I paid for J and there are tickets available, so would be good to receive also J. The agent however was unable to offer me a mixed-cabin trip leaving me with the choice of a full downgrade to Eco or waiting 4 more hours for the evening connection on which I was booked in J. Given that I had a long night in the train after me and preferred to get home earlier, I accepted to be downgraded to Eco for both legs. However I still found it strange, that a mixed cabin was not possible. Maybe that's a relevant info for somebody here in the forum, or maybe somebody was already able to get such a mixed cabin and I just got to an agent who did not know how to do it. In any case, I asked if the agent can manually upgrade the first leg again after downgrading the whole trip, but also this was not possible. I also explained the situation at check-in and the check-in agent was happy to upgrade me - against a fee, which I politely declined. I don't pay for an upgrade when I originally paid for J. I was however glad that the gate agent offered me 1A in the end, so I could enjoy my Champagne in J.
On the completely full A321 to ZRH however, I was stuck somewhere in the back, but since it was a short flight and AF brought me home earlier than originally booked, I was still more than happy.