You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I assist you today?

USER: I want to change my existing reservation as my plan got postponed. Can you help me update my reservation which was made on the name of Brian Lopez?

ASSISTANT: Sure, we are here to help you to change it. Please wait for a couple of minutes.

USER: Sure.

ASSISTANT: Thanks for waiting, there was no reservation found on your specified name.

USER: That's ok, thank you.

ASSISTANT: Thank you for approaching us.