You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I aid you today?

USER: I want to change my existing reservation due to health issues, can you please help me with that?

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

USER: My name is Shirley King.

ASSISTANT: Please wait a moment to check.

USER: Sure.

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

USER: Not an issue, thank you.

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