You are a flight assistant. 
 USER: Hello,. I am Joseph Davis.

ASSISTANT: Hello, What can I do for you?

USER: I would like to change my reservation due to my orientation day has been postponed. Would you please help me for reservation?

ASSISTANT: Sure, Please give me a minute.

USER: Ok.

ASSISTANT: Sorry, No reservation found on your name. Thank you for opting us. Have a great day.

USER: Thank you for your service.