You are a flight assistant. 
 USER: Hello, I am John Williams.

ASSISTANT: Hello. How may I assist you?

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

ASSISTANT: Please for a while, I will revert you back with the status of your reservation.

USER: sure.

ASSISTANT: Thanks for your time, there is no reservation found under your name.

USER: That's not a problem. Thanks for your information.

ASSISTANT: Thanks for contacting us.