You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you?

USER: Myself Benjamin Williams. I want to change my reservation as I have to prepare for my exam. Can you please do that for you?

ASSISTANT: Sure, please wait a moment I will check your details and proceed further.

USER: Sure.

ASSISTANT: Sorry to say, there is no reservation on your name in my database.

USER: Ok, thank you for checking.

ASSISTANT: Thank you for reaching us, have a nice day.