You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I am Catherine Martin. I want to change my reservation, can you help me?

ASSISTANT: Yes, give me a moment.

USER: Ok.

ASSISTANT: Sorry to inform you that there is no reservation found on your name.

USER: That's ok, thank you.

ASSISTANT: Thank you for consulting us.