You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Jacob Nelson. I want to change my previous reservation. Can you do this for me?

ASSISTANT: Sure, please wait for a while.

USER: Ok.

ASSISTANT: Sorry Nelson, there is no reservation found with your name in our records.

USER: That's fine. Thank you for checking.

ASSISTANT: My pleasure.