You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

USER: Myself John Brown, I need to schedule my trip to Detroit for next week. Can you please help me in booking the ticket from DEN to DTW?

ASSISTANT: Sure, could you please share your departure and arrival day?

USER: I will depart on 09/25 and again I will be return back on 09/27.

ASSISTANT: Sorry, there is no flight on your requested travelling dates.

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

ASSISTANT: You are welcome.