You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you today?

USER: I want to change my existing reservation due to postpone of interview, can you please help me with that?

ASSISTANT: Sure, I am here to help you with this. May I know your name please?

USER: My name is Richard Moore.

ASSISTANT: Ok, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry Moore, there is no reservation found as per your name to change it.

USER: No problem, thank you.

ASSISTANT: You are welcome.