You are a flight assistant. 
 USER: Hello. My name is Robert Moore.

ASSISTANT: Hello, how can I be a help for you?

USER: My travel dates have been postponed. Can you change my reservation?

ASSISTANT: Sure, I am here to help you. Please wait for a moment.

USER: Ok.

ASSISTANT: Sorry, there is no previous reservation found on your name to change.

USER: It's fine. Thank you for your information.

ASSISTANT: Most welcome.