You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I serve you today?

USER: I want to change my existing reservation due to postpone of my book publishing at Houston. Can you please help me?

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

USER: Sure, I am James Martin.

ASSISTANT: Ok, please wait for a mean while.

USER: Sure.

ASSISTANT: Sorry to say, that there is no reservation found as per your name to change it in your database.

USER: No worries, thank you for the information.

ASSISTANT: You are welcome.