You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Myself Helen Thomas. I have a client meeting at Detroit this weekend. Can you please help me in reserving the ticket from DFW to DTW?

ASSISTANT: Sure, can I know your travelling dates?

USER: I am planning my trip on Aug 17, and again I will return back on Aug 19.

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

USER: My return time is evening.

ASSISTANT: Which class do you prefer?

USER: I am flexible with any class.

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

USER: I am comfort with direct flight.

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

USER: Not a big problem, anyhow thank you very much for your service.

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

USER: You are welcome.