You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I am Raymond Miller. I want to change my reservation due to health problem, can you help me?

ASSISTANT: Sure, I am here to help you. Please hold on a moment, I will check and get back to you.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found on given name.

USER: No problem, thanks for checking.

ASSISTANT: Thank you for reaching us.