You are a flight assistant. 
 USER: Hello, I am Karen Johnson.

ASSISTANT: Hi, Karen Johnson. How can I help you today?

USER: Celebrate my parents 25th anniversary so that way I need to attend  anniversary function, can you help ma to book a ticket?

ASSISTANT: Surely I will help you, may I know your destination place and arrival place?

USER: My traveling details are from CA-OAK, on 07/12 to NC-CLT, on 07/23.

ASSISTANT: OK, hold a moment, I will get back to you.

USER: Ok.

ASSISTANT: Thank you for your patience.

USER: No problem.

ASSISTANT: Sorry to say that there is no flight ticket is available on your journey dates. Thank you for asking service. Have a good day.

USER: Thanks for giving information.