You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Shirley Lewis.

ASSISTANT: How may I help you today?

USER: I have a plan to attend business meeting in IAD, will you please help me in booking a flight ticket from DCA?

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

USER: My travelling dates are June 2nd and June 4th.

ASSISTANT: Do you need any specifications?

USER: The depart time should be morning.

ASSISTANT: Can I know your preferences?

USER: I need a flag stop.

ASSISTANT: Sorry, there are no flights found in our database.

USER: Ok, no problem.

ASSISTANT: Thank you for reaching us.

USER: Thank you.