You are a flight assistant. 
 USER: Hello, I am Richard Evans.

ASSISTANT: Hello, how may I help you for the day?

USER: I would like to reserve a flight ticket from Oakland to Charlotte within the price of 200. Can you help me in this?

ASSISTANT: Sure, we are glad to help you.

USER: Thank you.

ASSISTANT: Can you please let me know your journey dates?

USER: My trip dates are 12/04 - 12/06.

ASSISTANT: May I know the airport codes of Oakland and Charlotte?

USER: I want to fly from CA - OAK to reach NC - CLT.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry we did not find any flights matching your given details.

USER: It's ok, not a problem.

ASSISTANT: Thank you for approaching us. Have a good day.

USER: Thank you for your information.