You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Prepone plan came into a picture owing to announcement of birth of baby boy.

ASSISTANT: How can I help you today? Sure, may I know your name?

USER: So I need help to change an existing reservation.Can you please help me? My name is Benjamin Evans.

ASSISTANT: Ok, please wait for a while.

USER: Sure, I will wait.

ASSISTANT: Sorry to tell that there is no reservation on your name.

USER: That's not a problem.

ASSISTANT: Thank you for approaching us.

USER: Thanks for your kind information.