You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

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

ASSISTANT: Sure, I am glad to help you in booking. Can you please share your travel dates?

USER: I want to fly on June, 18 and return back on June, 20.

ASSISTANT: May I know your connection limit?

USER: I would prefer single connection.

ASSISTANT: Which class do you prefer?

USER: I am comfortable with any class.

ASSISTANT: Do you have any specification?

USER: No, thanks.

ASSISTANT: May I know your name for further process?

USER: Stephanie Evans here.

ASSISTANT: Sorry Stephanie Evans, no flights are available on your preferable travel dates.

USER: That's ok, thank you for the information.

ASSISTANT: Thank you for reaching us, have a nice day.