You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you?

USER: Can you aid me in booking a flight ticket from DCA to PHL?

ASSISTANT: Sure, please send your travelling dates.

USER: Sure, I would like to go on Jan 12th and return back on Jan 14th.

ASSISTANT: Do you have any class preference?

USER: Ensure it is in a economy class.

ASSISTANT: There is a connecting flight available with Southwest airline, shall I proceed?

USER: Ok, please proceed if the flight return time is in the evening.

ASSISTANT: May I know your name?

USER: Myself Lisa Roberts.

ASSISTANT: Sorry, there is no flight available with your requirements.

USER: That's ok, thank you for checking.

ASSISTANT: You are welcome, have a nice day.