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

ASSISTANT: Hello, how may I assist you today?

USER: As my friend's marriage is postponed, Can you please change my reservation?

ASSISTANT: Sure, Please wait a moment, I will check the reservation with your name to change it.

USER: Sure.

ASSISTANT: Thank you for waiting, We are sorry to inform you that there is no reservation with your name.

USER: Ok. Thank you.

ASSISTANT: Thank you for opting us, Have a great day ahead.