You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

USER: I am planning to visit Boston, will you help me in booking the flight ticket from DCA to BOS?

ASSISTANT: Sure, can you share me your travelling dates?

USER: My travelling dates are June 02 and June 04.

ASSISTANT: Do you have any class preference?

USER: I always prefer economy class.

ASSISTANT: Is there any other specifications?

USER: I need a connecting flight.

ASSISTANT: May I know your name please.

USER: Myself Dennis Collins.

ASSISTANT: Sorry, no flights are found on your travelling dates.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for reaching us.