Two questions:

First, to reconfirm, does changing the flight number from the UA codeshare flt # to native LH flight# on the UA purchased ticket (016) change anything (e.g. earnings, PQP, BIS for MM)?

Also, I had my PA change a flight I was booked on in biz both ways (unrelated to the above) all on UA metal that was EWR-NAP and FCO-EWR-IAH. Upon changing the outbound to a different date, the return downgraded to PE. My PA swears she did not click to change the return nor did she see anything noting a downgrade on it, it just popped up while choosing the new seats for the inbound. Was something just missed, or is this normal, or other shenanigans? I called and UA sorted the return back to biz, though it cost about ~$250. I asked when I called and the agent just said the downgrade was because I got moneyback as a FFC, but nowhere did it say that was for the return flight. Maybe that is what I get for not doing it myself, but is there a notice that was likely just missed on skimmed over due to a new fare class maybe? It was a first for me, though to be fair I don't make too many ticket changes as I tend to book with in 1-3 weeks of travel.