You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I be at your service today?

USER: Can you help me to book a flight ticket from PHX to DEN?

ASSISTANT: Sure, I will help you in booking the ticket. May I know your travelling dates please?

USER: My travel dates are Mar, 16 and Mar, 18.

ASSISTANT: Do you have any other specifications?

USER: I need direct flight.

ASSISTANT: Please help me with your name for booking.

USER: James Carter here.

ASSISTANT: Sorry for this inconvenience, I could not find any flight with your requirements.

USER: Not a problem, thank you for the information.

ASSISTANT: Thank you for reaching us.