You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I guide you today?

USER: I want to book the flight ticket from PHL to DEN. Can you please help me?

ASSISTANT: Sure, I will help you with that. Can you please provide your itinerary dates of travelling?

USER: My travel dates are Nov 10 and Nov 12.

ASSISTANT: Are you ok with connecting flight?

USER: Yes.

ASSISTANT: Do you have any other specifications?

USER: My return time should be in the evening.

ASSISTANT: May I know your name to book a flight ticket?

USER: Christopher Williams.

ASSISTANT: We regret to inform you that, there are no flights moving to your region with your requested preferences.

USER: Ok, thank you for the information.

ASSISTANT: Thank you for approaching us, hope you have a great day.