You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: Can you please help me to book a flight from DCA to PHL?

ASSISTANT: Sure, please provide your journey dates.

USER: My travel dates are May 31 to June 02.

ASSISTANT: Do you need any connection limit?

USER: I prefer connecting flight.

ASSISTANT: Do you need any other specifications?

USER: I would like to travel in business class.

ASSISTANT: May I know your name?

USER: I am Mark Adams.

ASSISTANT: There are no flights available on your routes.

USER: No problem, thank you for the information.

ASSISTANT: Thank you for choosing us.