You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: I am Kevin Wright.

ASSISTANT: How can I serve you?

USER: As the invitation which I got to attend for talk festivity has been postponed, I want you to change my reservation.

ASSISTANT: Ok, I will help you with that.

USER: Thank you.

ASSISTANT: Please, wait a minute.

USER: Sure.

ASSISTANT: Thank you for being patience. I am sorry to inform you that, there is no active reservation found on your name to proceed for modification.

USER: No problem. Thank you.

ASSISTANT: Thank you for approaching us, have a great day.