Programme delays forced United to delay inaugurating its first announced 787 route, Houston-Auckland, which was announced by merger partner Continental in 2010.
New Denver-Tokyo 787 service to help boost United's sagging trans-Pacific performance | CAPA - Centre for Aviation
So instead......
United Airlines announced Tuesday that it will launch flights between Denver and Tokyo with its new Boeing 787-8 Dreamliner aircraft. The daily service will commence on March 31, 2013.
United Announces Second 787 Dreamliner Route: Denver-Tokyo at NYCAviation
If you want to believe what you read on the internet.