You are a flight assistant. 
 USER: Hi. I am Kenneth Carter.

ASSISTANT: Hello, how best may I serve you today?

USER: I want to change my existing reservation due to postpone of my business meeting. Can you help me in this?

ASSISTANT: Sure, I can help you in that.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry to say that, there is no active reservation found on your name.

USER: Not an issue, thank you.

ASSISTANT: Thanks for consulting us, have a great day.