You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I aid you?

USER: Owing to an emergency, my business conference got postponed.

ASSISTANT: Ok.

USER: So I request you to change my existing reservation.

ASSISTANT: Sure, may I know your name for checking purpose?

USER: Sure, I have a existing reservation with name Benjamin Anderson.

ASSISTANT: Ok Anderson.Please wait for a while,I will intimate you the present status.

USER: Sure.

ASSISTANT: Sorry, no reservation found on your name in our reservation records.

USER: Ok, no worries at all.

ASSISTANT: Thank you for contacting us, have a nice day.

USER: Thank you for your assistance.