You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Debra Roberts here.

ASSISTANT: How may I assist you at this moment Debra?

USER: I want to attend a seminar in Washington. Can you please help me for booking the flight ticket?

ASSISTANT: Sure, I am oblige to help you with that. Can you please provide your preferable origin and destination airport codes for booking?

USER: My airport codes are from OAK to DCA.

ASSISTANT: May I know your departure and return dates of travelling?

USER: My travelling dates are from 12/17 to 12/19. Make sure my price limit is 200.

ASSISTANT: Thank you for providing your travel details. I will put the conversation on hold to check the best flights available in your route.

USER: Ok, I will wait.

ASSISTANT: We regret to inform you that, there are no flights moving to your region with your planned dates of travelling.

USER: Anyway, thanks for the information.

ASSISTANT: Thank you for reaching us, have a great day.