You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I'm Dennis Nelson, want to travel from DTW to DFW.

ASSISTANT: May I know your travelling dates?

USER: My travelling dates are from 08/21 to 08/23.

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

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

ASSISTANT: Most welcome.