You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

USER: I am Angela Collins. I want to book a flight ticket from ORD to DEN. Could you help me in booking?

ASSISTANT: Sure, can I know the travel dates please?

USER: My travelling dates are from 07/22 to 07/24.

ASSISTANT: Ok, wait a moment please.

USER: Sure.

ASSISTANT: Sorry, there are no flights available on your dates.

USER: That's ok, no problem. Thank you.

ASSISTANT: Thank you for approaching us.