You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you for the day?

USER: Can you please change my existing reservation?

ASSISTANT: May, I know your good name?

USER: Helen Walker here.

ASSISTANT: Please wait for a moment.

USER: Sure, take your name.

ASSISTANT: Sorry, we found no reservation on your given name.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for reaching us.