You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: Can you please assist me in booking a flight ticket from OAK to DCA?

ASSISTANT: Sure, we will help you in that.

USER: Thank you.

ASSISTANT: May I know your preferred travel dates?

USER: My preferable travel dates are from Apr 1st to Apr 3rd.

ASSISTANT: Is there any class preference?

USER: Yes, I prefer an economy class to travel.

ASSISTANT: Do you need any lay by in between your journey.

USER: I want a lay by in between my journey.

ASSISTANT: Any other specifications to be met?

USER: I want to depart in the afternoon.

ASSISTANT: Ok, please wait a minute.

USER: Ok.

ASSISTANT: Sorry to say that there were no flights found on your preferred dates.

USER: Ok, no problem.

ASSISTANT: May I know your name for record purpose?

USER: I am Donna Smith.

ASSISTANT: Thank you for reaching us.

USER: Thank you.