You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may I render you?

USER: Please book a flight ticket from Oakland, CA - OAK to Washington, DC - DCA.

ASSISTANT: Sure, can I have your trip dates?

USER: I wish to start my journey on 05/08 and return on 05/10.

ASSISTANT: Do you have any price limit?

USER: Price should not exceed 200.

ASSISTANT: May I know your good name please?

USER: My name is Shirley Mitchell.

ASSISTANT: Sorry, we did not find any flights running in your preferred dates.

USER: That's ok, not a problem. Thank you.

ASSISTANT: Thank you for reaching us.