You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you today?

USER: Please book me a ticket from DCA to IAD to meet my family.

ASSISTANT: Can I know your trip dates?

USER: I have planed to travel on July 14th and return on July 16th.

ASSISTANT: Do you need a connecting flight?

USER: I prefer connecting flight.

ASSISTANT: Do you need a economy class or a business class?

USER: I like business class.

ASSISTANT: Can I know your good name?

USER: Myself Scott Nelson.

ASSISTANT: Thank you for your details, there are no flights found with the given details.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you.