You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Joseph Martinez here.

ASSISTANT: How may I assist you?

USER: Can you book a flight ticket for my airport codes that is from BOS to DCA?

ASSISTANT: Sure, I will help you. May I know your planned travel dates please?

USER: The trip dates are from Aug 17 to Aug 19.

ASSISTANT: Can I have your name please?

USER: I am Joseph Martinez.

ASSISTANT: Do you need a connecting flight?

USER: I prefer a stopover flight.

ASSISTANT: May I know your other requirements?

USER: No, that is it.

ASSISTANT: Joseph Martinez, no flights has been found on your planned journey dates.

USER: Not a problem. Thank you.

ASSISTANT: Thank you for choosing us.