You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: Due to some entrepreneurship meeting, I am going to change my existing reservation. Can you help me?

ASSISTANT: May I know your name to proceed further?

USER: Nancy Green here.

ASSISTANT:  I am very sorry to inform you that there is no reservation found under your name in our database.

USER: No problem, thanks for the information.

ASSISTANT: Thank you for choosing us.