You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I aid you?

USER: Can you please help me in changing my existing reservation?

ASSISTANT: May I know your name?

USER: I am Brian Robinson.

ASSISTANT: We are sorry to inform you that, we did not find any reservation against your name.

USER: Ok, no issues.

ASSISTANT: Thank you.

USER: Thank you.