You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you?

USER: Please help me out in booking the ticket from DCA to PHL.

ASSISTANT: May I know your itinerary dates?

USER: My trip dates will be Mar 20 to Mar 22.

ASSISTANT: May I know your name?

USER: Patrick Moore is my name.

ASSISTANT: Sorry Patrick Moore, no flights are available on your route.

USER: That's ok, thank you.

ASSISTANT: Thank you for choosing us.