You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you today?

USER: My name is Virginia Young, I want to book a flight from PHX to attend a meeting with client. Can you book a flight to DEN?

ASSISTANT: Sure, please provide me your travel dates.

USER: I will fly on Dec 20 and return on Dec 22.

ASSISTANT: Do you have any connection limit?

USER: No, I want a direct flight.

ASSISTANT: Let me know about your class preference.

USER: I am fine with any class.

ASSISTANT: Do you have any airline preference?

USER: No.

ASSISTANT: May I know your depart and arrival timings?

USER: I want my return flight in evening.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: Sorry to say that, no flights are running on your routes.

USER: Ok, thank you for the information.

ASSISTANT: Thank you for contacting us.