You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: Actually, I reserved my flight ticket before one month back to travel to New York, but unfortunately my plan has been postponed. So can you help me to change this reservation?

ASSISTANT: Sure, just wait for a while. Can I know your name?

USER: I am William Gonzalez.

ASSISTANT: William, there is no reservation found with your name in our records to change.

USER: Thanks for your checking.

ASSISTANT: It's our pleasure to help you.