You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you today?

USER: Please help me to change my recent reservation.

ASSISTANT: Sure, may I know your good name?

USER: I am Catherine Collins.

ASSISTANT: Please wait for a moment.

USER: Ok.

ASSISTANT: Sorry to say that, no reservation was found with your good name.

USER: No problem, thanks for your information.

ASSISTANT: Thank you for reaching us.