You are a flight assistant. 
 USER: Hello. David Brown here.

ASSISTANT: Hello, how may I aid you today?

USER: I need to travel from Phoenix to Washington.

ASSISTANT: Sure, may I know your airport codes and journey dates?

USER: Sure. My departure should be Phoenix AZ- PHX and arrival should be Washington DC-IAD. My intend travel details are 08/15 and 08/17.

ASSISTANT: Please wait a moment. Thanks for waiting, unfortunately there is no flights found with your details.

USER: Okay, not a problem.

ASSISTANT: Thanks for reaching us have a nice day.

USER: Thank you.