You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

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

ASSISTANT: Sure, can I have your name to proceed?

USER: I am Nancy Green.

ASSISTANT: Please wait for a moment to check your details.

USER: Sure.

ASSISTANT: Sorry to say, no reservation found on your name.

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

ASSISTANT: Thank you for reaching us.