You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, How can I help you?

USER: I want to book a ticket from IAD to OAK. Could you book a ticket?

ASSISTANT: Sure, May I know the travelling dates?

USER: Travelling dates are Mar, 15 and Mar, 17.

ASSISTANT: Do you have any connection limit?

USER: I prefer connecting flight.

ASSISTANT: Is there any other requirements?

USER: I would like to prefer economy class.

ASSISTANT: May I know your name?

USER: My name is Sharon Campbell.

ASSISTANT: Please wait a minute.

USER: Sure.

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

USER: Thank you.

ASSISTANT: Thank you for opting us.