You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

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

ASSISTANT: Sure, may I know your name to check your reservation from our database.

USER: Ok, my name is Nicole Evans.

ASSISTANT: We regret to inform you that there is no active reservation found on your name to change.

USER: Ok, not an problem.

ASSISTANT: Thank you for opting us.

USER: Thank you for your help.