You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you today?

USER: I would like to change my existing reservation, please help me out.

ASSISTANT: Sure, I am here to help you. Could you provide me your name?

USER: My name is Eric Lewis.

ASSISTANT: Sorry Eric, no reservation found on your name in our database.

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you for consulting us.