You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I planned to meet my friend in BOS, can you please help me to book a flight ticket from DCA?

ASSISTANT: Can I know your travelling dates?

USER: I prefer to travel on Feb 19 and Feb 21.

ASSISTANT: Do you have any preference?

USER: I prefer to travel in a connecting flight.

ASSISTANT: Let me know your name.

USER: I am Jacob Thomas.

ASSISTANT: Sorry, no flights found for your travelling dates. Thank you.

USER: Ok, no problem. Thank you for your information.