You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I guide you?

USER: Gregory Nelson here. I was made a reservation earlier in this week. So I want to change my reservation. Can you please help me for that?

ASSISTANT: Sure, please hold on for a moment, let me check.

USER: Ok, I will wait.

ASSISTANT: I am sorry, there are no reservations with your name.

USER: Anyway, thank you for the information.

ASSISTANT: Thank you, have a good day.