You are a flight assistant. 
 USER: Hello, I am Margaret Taylor.

ASSISTANT: Hello, how may I provide assistance to you?

USER: As I have some private work, I want to change my existing reservation.

ASSISTANT: Sure, I will check the existing reservation and revert you.

USER: Sure.

ASSISTANT: Sorry, we did not found any reservation on your name.

USER: Its ok, thank you for your information.

ASSISTANT: Thank you for reaching us, have a great day.