You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you?

USER: I need to book a ticket from DCA to BOS. Could you book a ticket?

ASSISTANT: Sure, let me know your trip dates please?

USER: Trip dates are from Aug, 11 till Aug, 13.

ASSISTANT: Ok, is there any class preference?

USER: I am comfortable with any class preference.

ASSISTANT: Do you have any specific depart and arrival timings?

USER: I would like to depart in the afternoon time.

ASSISTANT: May I know your connection limit?

USER: I prefer connecting flight.

ASSISTANT: Do you have any airline preference?

USER: I prefer to fly in the normal-cost airline.

ASSISTANT: Can I know your name please to proceed further?

USER: My name is Thomas Campbell.

ASSISTANT: Sorry to inform you that there are no flight services available on your given details.

USER: Thank you.

ASSISTANT: Thanks for opting us.