You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

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

ASSISTANT: Sure, can you please let me know your name?

USER: My name is Laura Evans.

ASSISTANT: Sorry, there is no active reservation found under your name to change.

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

ASSISTANT: Thank you for reaching us.