You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: I would like to spend some more days with my best friend, so I want to change my existing reservation.

ASSISTANT: Ok, may I know your name please?

USER: My name is Robert Evans.

ASSISTANT: Sorry Robert, there are no flights reserved on your name.

USER: Ok, no problem, thank you for your information.

ASSISTANT: Thank you for opting us. Have a good day.