Not mine but I read from another on here:
For flights that have wifi - even if you dont pay, you can still access United Services. There was one guy who wanted a specific rebooking option he couldn't get. He would email his itinerary to his wife via ua.com , and there was an option to add a note. So he would email her, for free, his situation and what exact flights/rebooking help he was looking for so his wife could call and get him rebooked.
Always thought that was neat.