You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I am planning to visit Washington, will you help me in booking the flight ticket from OAK to IAD?

ASSISTANT: Sure, let me know your travelling dates.

USER: My preferable journey dates are Mar 23 and Mar 25.

ASSISTANT: Do you want connecting flight or direct flight?

USER: I need a flight with single connection.

ASSISTANT: Do you have any other requirements?

USER: No, I didn't have any other specifications.

ASSISTANT: May I know your name please?

USER: Myself Lisa Lee.

ASSISTANT: Sorry, there are no flights found with your given details.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for opting us.