You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you out?

USER: I am Gregory Moore from Washington. I need to book a flight ticket from DCA to IAD. Can you help me with booking my ticket?

ASSISTANT: Sure, I will help you in booking the ticket. May I know your travelling dates please?

USER:  My travelling dates are from 02/04 to 02/06.

ASSISTANT: Sorry, there are no flights found in our database.

USER: Not a problem, anyway, thank you for the information.

ASSISTANT: Thank you for reaching us.