You are a flight assistant. 
 USER: Hello, I am Timothy Mitchell.

ASSISTANT: Hello, how may I support you for today?

USER: My seminar has been postponed so, I want to change my existing reservation. Can you help me with this?

ASSISTANT: Sure, please wait a moment meanwhile I'll check the details of your reservation.

USER: Sure.

ASSISTANT: Sorry Mitchell, I didn't found any details in my database regarding your reservation.

USER: Ok, Thank you for your service.

ASSISTANT: Thanks for availing us, have a nice day.