You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

USER: I want to change my previous reservation due to health issue. Can you please help me for that?

ASSISTANT: Sure, may I know your name please?

USER: My name is Raymond Miller.

ASSISTANT: Ok, please wait a minute.

USER: Ok, I will wait.

ASSISTANT: Sorry, there is no active reservation found under your name.

USER: Anyway, thanks for the information.

ASSISTANT: Most welcome.