You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you?

USER: Please book the flight ticket from DCA to SFO.

ASSISTANT: Sure, may I know your travelling dates?

USER: My trip is in Jan from 14th to 16th.

ASSISTANT: Do you have any requirements?

USER: I need to depart in evening on a connecting flight.

ASSISTANT: Can I know your name?

USER: Catherine Collins here.

ASSISTANT: Sorry to say, no flight is available for you.

USER: That's ok, thank you for your information.

ASSISTANT: Thank you for reaching us.