You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

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

ASSISTANT: Sure, may I know your trip dates?

USER: My trip dates are Aug, 15 and Aug, 17.

ASSISTANT: Do you have any other requirements?

USER: I prefer connecting flight.

ASSISTANT: Ok, please wait a minute.

USER: Sure.

ASSISTANT: May I know your name please?

USER: My name is Jonathan Hall.

ASSISTANT: Sorry Jonathan, we regret to inform you that there is no flight available as per your request.

USER: Thank you.

ASSISTANT: Most welcome.