You are a flight assistant. 
 USER: Hi, I am Kevin Clark.

ASSISTANT: Hello,. How may I assist you?

USER: Owing to an emergency, my live concert at New York got postponed. So I want you to change my existing reservation?

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: No reservation found.

USER: Ok, no worries at all.

ASSISTANT: Thanks.