You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, may I know your name?

USER: Myself Paul Smith.

ASSISTANT: Yes, Smith how can I serve you?

USER: I have planned to go for ceremony in AUS but I have important meeting in DTW. So can you please change my existing reservation?

ASSISTANT: Sure, I am here to help you. Sorry, there is no reservation under your name in our data base to change.

USER: Ok, fine thank you for your help.

ASSISTANT: Most welcome, thank you for choosing our services.