You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, may I know what kind of service you are expecting from us?

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

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: It will be helpful for me, If you share me your good name please?

USER: Myself Angela Walker.

ASSISTANT: Please stand by.

USER: Sure.

ASSISTANT: Thanks for your time, we are regret to inform you that, there is no active reservation found in your given name.

USER: No issue, Thanks for the information.

ASSISTANT: Thanks for choosing our services, we will try to serve you for the next time.