You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I be a help for you?

USER: My name is Andrew Carter. I just need your help in changing my existing reservation details.

ASSISTANT: Ok, please wait for a while.

USER: Ok.

ASSISTANT: Sorry, there is no reservation found on your name in our database to change.

USER: That's ok, thanks for the information.

ASSISTANT: You are welcome.