You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I be of your assistance?

USER: I am Kevin Smith. I am planning to change an existing reservation, due to health issue. Can you please change my reservation?

ASSISTANT: Sure, please wait for a minute.

USER: Sure, take your own time.

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

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

ASSISTANT: Thank you for availing us.