You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I am Catherine Collins. I want to change my existing reservation due to postpone of my seminar.

ASSISTANT: Sure, please wait for a while.

USER: Sure.

ASSISTANT: Thanks for waiting, There is no reservation on your given name.

USER: No problem, thank you.

ASSISTANT: Thank you for opting us.