You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: I want to change my reservation due to some issues, so please change it.

ASSISTANT: Sure, I am gleeful to help you but I need your name to change that reservation.

USER: Sure, I am Charles Lee.

ASSISTANT: Sorry, I could not find any reservation with your name in our database. Thanks for choosing us, have a great day ahead.