You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I guide you for today?

USER: Myself Dennis Gonzalez. I would like to change my existing reservation, which is done recently. Can you please help me out?

ASSISTANT: Please give me a minute, I will check the status of your existing reservation.

USER: Thank you for considering my request.

ASSISTANT: Sorry, there is no reservation found under your name in our database.

USER: Ok, no problem, anyway thank you for the information.

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