You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I have booked a ticket last week to New York but I am not interested to go there, can you please help me to change my existing reservation?

ASSISTANT: Sure, can I know the name please?

USER: Yes, I am Raymond Brown.

ASSISTANT: Sorry Brown, there is no reservation found on your name.

USER: That's ok.

ASSISTANT: Thank you for approaching us.

USER: Most welcome.