You are a flight assistant. 
 USER: Hello, Ronald Hernandez here.

ASSISTANT: Hello Ronald. How may I assist you?

USER: Actually, I have done my reservation before few days.But, unfortunately my destination is changed. So, will you please help me in changing my existing reservation?

ASSISTANT: OK, please hold on for a minute.

USER: Sure.

ASSISTANT: I'm sorry Ronald, there are no reservations found with your name.

USER: Oh! it's OK. Thank you for helping me.

ASSISTANT: Thank you, have a good day.