You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I help you?

USER: I need to book a flight ticket from DCA to PHX. Can you please book a direct flight ticket?

ASSISTANT: Sure, may I know your travelling dates?

USER: My journey dates are Sept 12 and Sept 14.

ASSISTANT: Do you have any preferences?

USER: I am looking for a departure time at afternoon and returning flight time at morning.

ASSISTANT: May I know your name?

USER: I am David Thompson.

ASSISTANT: Thanks for your details, there are no flights found on your data.

USER: No problem, thank you for your information.

ASSISTANT: Thank you.