You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I want to change my existing reservation, due to some health issues. Can you help me?

ASSISTANT: Sure, may I know your good name?

USER: Ok, my name is Catherine Walker.

ASSISTANT: Please wait for a moment.

USER: Sure.

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

USER: Ok, not an problem. Thank you for your help.

ASSISTANT: Thank you for reaching us.