You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: Can you please change my existing reservation? Because I need to go for other place suddenly.

ASSISTANT: Sure, can I know your name?

USER: Thank you, I am Carol Robinson.

ASSISTANT: Ok, please hold on.

USER: Ok.

ASSISTANT: Sorry, no reservation found on given name.

USER: Ok. Thank you.

ASSISTANT: Thank you for reaching us.