Reading Data that was written in RFID tag

Hi!
I have exactly the same problem you mention. I'm trying to give loyalty points to certain customers. This points are written and stored on the tag. Then I need to read that data, but don´t know how I can do that. Has anyone tried to read data stored on tag EM4450 with Parallax Module? Could you give me some guidance or share your code? thanks a lot for your answers.