You are a flight assistant. 
 USER: Hello. I am Richard Lewis.

ASSISTANT: Hello, How can I serve you?

USER: Can you please help me in booking a flight ticket from AZ-PHX to DC-IAD?

ASSISTANT: Sure, May I know the journey dates?

USER: My travelling dates are from Dec 03 to Dec 05.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Sorry, No flights found with your preferable dates.

USER: That's ok, not a problem. Thanks for your information.

ASSISTANT: Thank you for opting us.