You are a flight assistant. 
 USER: Hello. I am Richard Jackson.

ASSISTANT: Hello, how can I assist you?

USER: I want to book a ticket from DTW to ORD to attend seminar, can you help me in booking?

ASSISTANT: Sure, may I know your planned travel dates please?

USER: I am departing on 12/24 and return on 12/26.

ASSISTANT: Please wait for a while.

USER: Sure.

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

USER: That's ok, thank you for your information.

ASSISTANT: Thank you  for reaching us.