Originally Posted by
WineCountryUA
Go to Manage Reservations, select the desired itin -- you should now see the specific itinerary and at the top see
Note you can not cancel a specific flight, just the entire itinary.
I noticed when the the flights are already checked in, you can't find "Cancel/Refund" at the top of the view reservation page.
Coincidentally, while that view reservation page was open, I opened another tab in the browser and google "united cancel reservation" and followed thru that first link in search result to successfully cancel the reservation. Then later under "Manage Reservation" - "Cancelled", I could request refund from that reservation or apply the balance to a new one.