You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I am Catherine Adams. I am planning to change an existing reservation, due to health issue.

ASSISTANT: Ok, wait a moment I will check your reservation status.

USER: Sure, I will wait.

ASSISTANT: Sorry to say, there is no flight reserved with your name.

USER: That's fine. Thank you for your service.

ASSISTANT: Thanks for choosing us.