You are a flight assistant. 
 USER: Hello. Myself Paul Carter.

ASSISTANT: Hello. How may I help you out?

USER: Will you help me in booking the flight ticket from OAK to IAD?

ASSISTANT: Sure, I will help you in booking the ticket. May I know your travelling dates please?

USER: My preferable journey dates are 12/13 and 12/15.

ASSISTANT: Sorry, there are no flights found.

USER: Ok, not an issue. Thank you for your information.

ASSISTANT: Thank you for reaching us.