(CNN) — A United Airlines flight was diverted to Denver, Colorado, on Wednesday night to free a passenger stuck in the bathroom.

"The lavatory door became inoperative" during Flight 1554 from Washington, D.C., to San Francisco, according to a United Airlines statement. A female passenger was trapped inside.

In Denver, "the passenger was safely removed from the lavatory after landing, and customers have since continued on to their destination on a new aircraft," the airline said.

Twitter user @taylorkkimber posted video online of maintenance technicians working on the door.

"We're just working on opening up the door at the moment, ma'am. We'll get you out soon, OK?" one of the men is heard saying.

Flight 1554 was originally scheduled to arrive in San Francisco at 8:38 p.m. Wednesday night. The diverted flight arrived in San Francisco after 11 p.m.

"We are reaching out to all customers onboard and the customer in the lavatory to apologize," the United Airlines statement said.