You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Helen Wright.

ASSISTANT: How may I aid you?

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

ASSISTANT: Sure, I am here to help you out.

USER: Thank you.

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

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

ASSISTANT: Thank you for choosing us.