You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: Margaret Allen here. I want to travel from PHL to DEN.

ASSISTANT: May I know your trip dates?

USER: My travelling dates are from 01/31 to 02/02.

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

USER: That's fine, thank you.

ASSISTANT: My pleasure.