You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you at this moment?

USER: Myself Nicholas Campbell. I am planning my holiday trip to visit Detroit. Can you please help me in reserving the ticket from IAD to DTW?

ASSISTANT: Sure, I am here to help you with the ticket booking. Can you please share your travel dates?

USER: I am planning to leave on Sept 17 and again I will return back on Sept 19.

ASSISTANT: Ok, do you have any class preference?

USER: I am comfort with any class.

ASSISTANT: Ok, please be on hold for a minute.

USER: My return timne is evening.

ASSISTANT: Sorry to inform you that, there is no flight available in this route on the dates you have mentioned.

USER: Not a big deal, anyway thank you very much for your service.

ASSISTANT: You are most welcome. Thank you for reaching us.