You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I am Patrick Nelson. I would like to change my reservation as I am leaving for friend's marriage, can you please help me out?

ASSISTANT: Sure, please wait for a while.

USER: Ok.

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

USER: Ok no problem, thank you for your services.

ASSISTANT: You are welcome.