You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I serve you?

USER: Prepone plan came into a picture owing an announcement of birth of baby boy. So I need to change an existing reservation, can you please help me?

ASSISTANT: Sure, May I know your name?

USER: My name is John Hernandez.

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: Sorry, No reservation found on your name.

USER: That's not a problem.

ASSISTANT: Thank you for availing us.

USER: Thank you.