You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I am Joshua Lewis. I want to change my reservation.

ASSISTANT: Ok, I can help you with changing your reservation.

USER: Ok.

ASSISTANT: Please wait for a moment till I check with your existing reservation.

USER: Sure.

ASSISTANT: I am very sorry to inform you, there is no reservation found by your name.

USER: Ok, fine thank you for checking.

ASSISTANT: Thank you for connection with our services.