Just tried to make a simple date change online and was only partially successful. Went through all the screens and everything looked good, no additional miles were needed and I was even getting a refund of $0.90, but when I tried to confirm got the dreaded error msg asking me to call United Reservations. I can see the flight under My Reservations with the new date along with the msg that "a change has been made to your itinerary. Please call United Reservations to have your ticket reissued". blah.