Same day changes on LH Z fare?
I've searched and have found various threads on standby options on fares when traveling on LH but haven't found anything really on point when dealing with a Z fare. About a month ago I booked a combination UA/LH z fare for myself for the end of December SFO-FRA-FCO-FRA-SFO.
I then booked a separate reservation for my GF about three weeks later when her schedule freed up and allowed time to accompany me. I was able to get her on 3 of the 4 segments with me, but when I booked her ticket, the connecting flight from FCO to FRA was not available in Z, so I booked a flight leaving 3 hours earlier than mine. Now it looks like there is a z fare open on my FCO-FRA segment. Can I change my GF's reservation to my flight? The fare rules sent to me say "penalty" for changing but are not specific as to opening leg, changing dates, and are not clear whether a change on the originally ticketed day of travel but a marginally later flight would be permitted. Would love any insight from anyone who might have dealt with this specifically on a z fare issued by LH.