You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: I am Joseph Lewis. I want to change my existing reservation due to postpone of my meeting. Can you help me with that?

ASSISTANT: Sure, please wait for a while.

USER: Thank you. Sure.

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

USER: No problem, thank you for the information.

ASSISTANT: Thank you for reaching us.