You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: My name is David Gonzalez. I would like to visit Detroit. Can you help me for booking a flight ticket from DFW to DTW?

ASSISTANT: Sure, can I know your travelling dates?

USER: My travelling dates are Jan 17 and Jan 19.

ASSISTANT: Do you have any particular time for departing and returning?

USER: My departure time is morning.

ASSISTANT: Which class do you prefer?

USER: Any class is fine for me.

ASSISTANT: Would you like to prefer direct flight or connecting flight?

USER: I prefer to book a single connecting flight.

ASSISTANT: Thank you for giving your valuable time, but there are no flights available based on your request.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for opting us, we hope to serve you again with better features.