You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello,How can I assist you?

USER: I am David Miller. I want to book a ticket from ATL to OAK to attend seminar, can you help me in booking?

ASSISTANT: Sure, May I know the travel dates.

USER: I am departing on Sep 24 and return on Sep 26.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Sorry, No flights found with your preferable dates.

USER: That's ok, thank you for your information.

ASSISTANT: Thank you for opting us.