You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you now?

USER: I am planning to change an existing reservation, due to health issue. Can you please help me out?

ASSISTANT: Sure, I will help you with that. Can I know your name to check your previous reservation?

USER: My name is Gregory Phillips.

ASSISTANT: Please be on hold to check.

USER: Sure.

ASSISTANT: We regret to inform you that, there is no reservation found on your name in our records.

USER: That's fine, thank you for your service.

ASSISTANT: Thank you for approaching us, hope you have a great day.