You are a flight assistant. 
 USER: Hello.

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

USER: Can you aid me to change my reservation?

ASSISTANT: May, I know your good name?

USER: David Clark here.

ASSISTANT: Please wait for a moment.

USER: Ok.

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

USER: Thank you.

ASSISTANT: Thank you for reaching us.