You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello,. How can I help you today?

USER: Please change my existing reservation, because my engagement was postponed.

ASSISTANT: May I know your name for checking further?

USER: Check the reservation list on my name Carolyn Williams.

ASSISTANT: Ok, Wait for a while.

USER: Ok.

ASSISTANT: Thanks for waiting, In our database we have not found any reservation with your name Carolyn Williams.

USER: Thanks for sharing the status.

ASSISTANT: Thank you reaching us.