You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: I want to book a flight from DCA to visit PHX for vacation. Can you book a flight for me?

ASSISTANT: May I know your trip dates?

USER: I will fly on Feb 19 and return on Feb 21.

ASSISTANT: Do you have any connection limit preference?

USER: I prefer a direct flight.

ASSISTANT: Do you have any other specifications?

USER: No.

ASSISTANT:  Could you help me with your name please?

USER: My name is Joshua Green.

ASSISTANT: Sorry, there is no direct flight available for the given dates.

USER: Ok, thank you for the information.

ASSISTANT: Thank you for reaching us.