You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Betty Miller.

ASSISTANT: how can I help you?

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

ASSISTANT: Just a moment please.

USER: Ok, take your time.

ASSISTANT: I am sorry no reservation found on your name.

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