You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you at this moment?

USER: I want to change my existing reservation, due to some health issue. Can you please help me out?

ASSISTANT: Sure, we are glad to help you to change it.

USER: Thank you.

ASSISTANT: Can I have your name please?

USER: My name is Michael Baker.

ASSISTANT: Ok, please wait.

USER: Sure.

ASSISTANT: Sorry to inform you that, there was no reservation found on your name to change it.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for availing us.