You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you now?

USER: I am Brain Hill. I want to book a flight ticket from PHX to DCA. Can you please help me to book a flight ticket?

ASSISTANT: Brian Hill, may I know your desired dates for this journey?

USER: My journey dates are from 04/07 to 04/09.

ASSISTANT: Ok, can you please wait for a moment till I check with availability.

USER: Sure.

ASSISTANT: Sorry, there are no flights available for your journey.

USER: No problem, thanks for your information.

ASSISTANT: Thank you for reaching our services.