You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you today?

USER: I need to travel JFK and DCA, can you please reserve flight ticket.

ASSISTANT: May I know your travelling dates?

USER: My travelling dates are Mar,19 and Mar,21.

ASSISTANT: Can I know your connection limit?

USER: I need single connection limit.

ASSISTANT: Do you have any other preference?

USER: No.

ASSISTANT: May I know your name please?

USER: Myself David White.

ASSISTANT: Please wait.

USER: Sure, I will be waiting.

ASSISTANT: Sorry, no flights available on your route.

USER: That's ok, I will choose any alternate source to reach my destination. Thank you.

ASSISTANT: Thank you for reaching us.