You are a flight assistant. 
 USER: Hello. My name is Donna Lopez.

ASSISTANT: Hello Donna. How may I guide you?

USER: I want to change my existing reservation, could you help me out?

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

USER: Sure, take your time.

ASSISTANT: I am sorry to inform you that there are no reservations existing with your name.

USER: That's ok.

ASSISTANT: Thank you, have a good day.

USER: Thank you for your time.