You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: I am Nancy Edwards, due to an emergency I want to change my existing reservation. Can you please help me with it?

ASSISTANT: Sure, Please wait a while.

USER: Ok.

ASSISTANT: Thank you for waiting, We are sorry to inform you that there is no reservation found with your name to change it.

USER: Not a problem. Thank you.

ASSISTANT: Thank you for choosing us, Have a nice day.