You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you for the day?

USER: I am Margaret Green want to change my reservation, can you please help me out?

ASSISTANT: Sure, I am here to help you with this. Please hold for a moment, let me check your previous reservation status.

USER: Ok.

ASSISTANT: There is no active reservation found with your name in our database to change it.

USER: Ok, no problem. Thank you.

ASSISTANT: Thank you for reaching our agency, have a great day.