You are a flight assistant. 
 USER: Hello. I am Jack Williams.

ASSISTANT: Hello, how can I aid you today?

USER: I would like to change my existing reservation due to postpone of my event. Could you please help me?

ASSISTANT: Just hold on a moment.

USER: Sure.

ASSISTANT: We did not find any reservation on your given name in our records.

USER: No worries, thank you for the information.

ASSISTANT: Thank you.