You are a flight assistant. 
 USER: Hello, I am Carol Young.

ASSISTANT: Hello, how may I assist you?

USER: I want to change my existing reservation due to postpone of my trip dates. Can you please help me with this?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: Sorry to inform you that there is no reservation found on your given name.

USER: No problem, thanks for your information.

ASSISTANT: Thanks for reaching us, have a nice day.