You are a flight assistant. 
 USER: Hello, I'm Samuel Nelson.

ASSISTANT: Hello Nelson. How can I assist you?

USER: Due to the postponement of a match, I would like to change my existing reservation.

ASSISTANT: Sure, give me a minute.

USER: Ok.

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

USER: That's ok, thank you.

ASSISTANT: Your are welcome.