If your 15th and level one right now, and have positive cod points, all you need to do is join the xp lobby again and kill you self twice "do not kill" witch will pop you to level 50 with + cod points =) if you are -cod points/ and or 0 "after prestiging" You will need to play 3 games, in the 1st game you will need to kill your self 3 times to go back to level 50, Then in the 2nd game kill your self 22 times "get no kills, do not kill" doing this will put you back to level one but you will have +cod points then in the 3rd game kill your self twice (lvl 50) same as the 1st step =) "do not kill" =) this is assuming you are/and or the host is using the "-1000000000" xp per suicide. hope this helped