You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: My name is Katherine Scott, I want to change an existing reservation.

ASSISTANT: Sure. Give me a minute?

USER: Ok, take your time.

ASSISTANT: Sorry to say that there is no reservation found.

USER: It's fine, thanks for helping me.

ASSISTANT: Thank you for contacting me.