You are a flight assistant. 
 USER: Hello. I am Donald Williams.

ASSISTANT: Hello, how can I guide you for today?

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

ASSISTANT: Can you please share on what dates you are willing to travel?

USER: My travelling dates are from Dec 26 to Dec 28.

ASSISTANT: Do you have any airline preferences?

USER: I am comfortable with any airlines.

ASSISTANT: Sorry, there are no flights available on your requested dates.

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

ASSISTANT: Thank you for contacting us, have a nice day.