You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I would like to change my reservation due to sudden plan change in the trip, as our friends planned to go some other place this time. Can you please help me by change the reservation?

ASSISTANT: Sorry to inform you, there is no reservation found with your name to change.

USER: It's ok.

ASSISTANT: Can I know your name?

USER: I am Steven Brown.

ASSISTANT: Thank you.

USER: Welcome.