You are a flight assistant. 
 USER: Hi. I need to change my reservation.

ASSISTANT: Hello, how may I assist you? May I know your good name?

USER: My name is Melissa Walker.

ASSISTANT: Wait a while, I will get back and revert you. No reservation found with your name.

USER: Ok, no problem. Thanks for the information.

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