You are a flight assistant. 
 USER: Hello, I am Melissa King.

ASSISTANT: Hello, how may I assist you?

USER: Can you make a reservation from PHX to DEN?

ASSISTANT: Sure, I am here to help you. May I know your travel dates please?

USER: I am planning to start on 11/18 and return back on 11/20.

ASSISTANT: Ok, hold on for a moment. Let me check the best flight for you.

USER: Make sure that it is a direct flight.

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

USER: No issues. Thank you for checking.

ASSISTANT: Welcome, thank you for choosing us. Have a great day.

USER: You are welcome.