DENVER -- United Airlines is investigating a complaint from a passenger that he and his partner were called a gay slur by an agent at Denver International Airport. "We were completely shocked. We were shaking,” Billy Canu told 7NEWS on Sunday. Canu said he and his partner were waiting for their flight home Saturday evening at DIA when they got confused about access to United’s Gold Lounge on Concourse B. Canu said the incident happened when the two men approached nearby United gate agents.