Dont do it! You lose all your emblems and titles and you go back to Prestiage one.Your not going to lose your classes, but your not going to get the tokens back either
You just lose all titles and emblems, score (Play time, KD and score) and anything unlocked via prestige token but you do keep game mode leader boards. Also, you will not have any prestige tokens when rested. Note: If you get reset by IW you will lose EVERYTHING bar from loses and deaths.