You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I assist you?

USER: Please book a flight ticket from DCA to DTW?

ASSISTANT: Sure, May I know the travelling dates?

USER: My journey dates are Aug 18 and Aug 20.

ASSISTANT: Do you have any connection limit?

USER: I need a connecting flight.

ASSISTANT: Is there any other requirements?

USER: I prefer a economy class.

ASSISTANT: May I know your name?

USER: I am Sarah Jackson.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Sorry, No flights found with your preferable dates.

USER: No problem, thank you for your information.

ASSISTANT: Thank you for availing us.