You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Larry Roberts.

ASSISTANT: How can I assist you today?

USER: I want to book a flight ticket to Chicago, IL - ORD to meet my brother. Please help me in booking a flight ticket.

ASSISTANT: Sure, may I know your source airport code please?

USER: My source airport code is Oakland, CA - OAK.

ASSISTANT: Can you please provide your planned travel dates?

USER: My trip dates are from 08/10 to 08/12.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Sorry to inform you that there are no flights available for you on those dates.

USER: No problem, thanks for your information.

ASSISTANT: Thank you for reaching us.