1 ) Login to the account that will receive the duplication.
2 ) Go to multiplayer in the home.
3 ) Turn and join your second controller doing "as a guest".
4 ) Go to "Store" and press twice the "X/A" key quickly with your second controller.
5 ) A little time after this, press the "O/B" with your first controller.
6 ) If everything went well, you should be just before the menu access to multi.
7 ) An error message is present, confirm with your first controller.
8 ) A drop down menu with your accounts will therefore open, select the account that will give the prestige, stats, etc. ..
9 ) Go to the Home multiplayer, you will see the PSN ID/XBL GT of the account you just select and not the one on which you are connected.
10 ) Disconnect and reconnect the PSN/XBL.
11 ) Join a public match with the duped level !
12 ) Now it sticks to your account, congratulations you've hacked your prestige level !