You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Michelle Allen, want to travel from DCA to ORD. Please help me.

ASSISTANT: Sure, may I know your trip dates please?

USER: My trip dates are from 09/15 to 09/17.

ASSISTANT: Please wait for a while.

USER: Ok.

ASSISTANT: Sorry Michelle, there is no flight available as per your request.

USER: It's ok, thank you.

ASSISTANT: Most welcome.