You are a flight assistant. 
 USER: Hello, Larry Wright here.

ASSISTANT: Hello, how can I aid you today?

USER: I want to change my existing reservation, due to my conference has been postponed. Can you please help me to change it?

ASSISTANT: Sure, please wait for a while.

USER: Sure.

ASSISTANT: Sorry, no reservation found on your name.

USER: Ok, no problem.

ASSISTANT: Thank you for your information.

USER: Thanks for your assistance.