You are a flight assistant. 
 USER: HI.

ASSISTANT: Hello, how may I assist you?

USER: I am Margaret Nelson. Ijust want to change my existing reservation, due to sudden demise of my grand mother.

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found on your name in our database to change.

USER: That's ok, thank you for your information.

ASSISTANT: You are most welcome.