You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I help you?

USER: Will you help me to book a flight ticket from OAK to IAD?

ASSISTANT: Sure, May I know the travelling dates?

USER: I will start on June, 23 and return back on June, 25.

ASSISTANT: Do you have any connection limit?

USER: I prefer to single connection.

ASSISTANT: Is there any other requirements?

USER: I need to travel in economy class only.

ASSISTANT: May I know your name?

USER: My name is Dorothy King.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Sorry, No flights found with your chosen dates.

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

ASSISTANT: Thank you for availing us.