You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: My name is Angela Thomas. My friend marriage party was postponed, so please change my existing reservation.

ASSISTANT: Sure, please wait a minute I will check and revert you.

USER: Ok.

ASSISTANT: Thank you for waiting, sorry to inform you there was no flight found on your name.

USER: Ok, thanks for your service.

ASSISTANT: Thank you for availing with us.