UAL Flight 488 Deleted but passengers boarding

Flight UAL 488 KSAT to KDEN Feb 16/2015 4.46pm has been delayed about 3 hours. Just prior to passengers boarding at 7:30pm. the flight was no longer listed. Yet my wife is still boarding the aircraft. No other flights to KDEN are listed for this time tonight either. What is the reason for de-listing this flight? I can no longer track the flight to help my wife get a connecting flight to Burbank the replace the one she obviously missed.

Does United do this to cover up large delays to make their on-time record look good?

http://flightaware.com/live/flight/UAL488/history/20150216/2249Z/KSAT/KDEN

So much for that conspiracy theory…

Refiled the flight plan?