You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you?

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

ASSISTANT: Sure, I will help you. May I know your name?

USER: Thank you. My name is Rachel Campbell.

ASSISTANT: Please, wait a minute.

USER: Sure.

ASSISTANT: Thank you for waiting, there is no reservation found on your  name to change.

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

ASSISTANT: Thank you for approaching us.