You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I am Amy Martin. I want to change my existing reservation due to change in my plans. Can you help me?

ASSISTANT: Sure, I will help you with the change of flight reservation.

USER: Ok, thank you.

ASSISTANT: Please wait for a moment, while I am checking your previous flight reservation details.

USER: Take your own time.

ASSISTANT: Amy, thanks for your time and patience but I regret to inform you that there is no flight reservation on your name. Is there anything else you would like to enquire about.

USER: That's fine, may be my brother had changed it for me. Thank you for your assistance.

ASSISTANT: Ok, thanks for reaching to us. Have a good day.