You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you today?

USER: My name is Michael Lopez. I want to do some changes in my existing reservation. Can you help me for that?

ASSISTANT: Sure, I will help you in changing the reservation.

USER: Thank you.

ASSISTANT: Please allow me a moment.

USER: Sure, take your time.

ASSISTANT: Sorry Lopez, there is no active reservation on your name.

USER: That's ok, thank you for checking.

ASSISTANT: Ok, thank you for reaching us.