Can I sneakily upgrade a friend's flight?
My girlfriend is visiting her mother in Zurich, and will be booking a round-trip ticket to fly home from Zurich to San Francisco. (It's complicated ... she uses the "return" trip to fly back out to Zurich in the next year, and visit her mother again, and repeats the process. So she typically specifies an arbitrary "return" flight date that is about a year out, maybe Christmas or summer, and commonly ends up changing it and paying the change fee once plans solidify though sometimes keeps it as is).
Anyway, if I know her confirmation number and her full name etc, is it possible for me to sneak and upgrade her to a business class flight? Would I need to upgrade both legs of the ticket? If I do this, does the 'change' fee become more expensive?
Thanks for your help!!