I have had cases recently where the original itinerary and the changed itinerary show up, one above the other when I log in. I am asked to accept the change(s) before I can do anything else with the res or call in for any other changes I need to make. This is rare and also very recent.
Most of the time I am completely locked out requiring a phone call. Very annoying and a complete waste of two peoples' time and, as others have said, very inefficient. And, most of the changes have been to add or remove a few minutes from the flight time. No aircraft swap or other schedule changes. Why does it matter if my flight ANC-SEA is 3 hours 12 minutes or 3 hours 9 minutes?