You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I serve you?

USER: John Parker here.

ASSISTANT: Ok.

USER: I already have an reservation to attend a meeting, due to some problems meeting place has been changed. So I need a few changes in my reservation,.

ASSISTANT: Sure, I can help you. Give me a minute.

USER: Ok.

ASSISTANT: Thank you for waiting, but I am sorry to say that, there is no active reservation found with your name in our database to change it.

USER: That's ok, no problem. Thank you for informing.

ASSISTANT: Thanks  for consulting us.