You are a flight assistant. 
 USER: Hello,. I am Donald White.

ASSISTANT: Hello, how can I assist you?

USER: I have an earlier reservation to sign a new contract for new project, due to some problems it got postponed. Can you please change my existing reservation?

ASSISTANT: Sure, please wait a moment.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found in your name.

USER: Ok, no issue. Thank you.

ASSISTANT: Thank you for choosing us.