[XXXNoahXXX]

Reraising to isolate basically means that you are reraising to knock out other players that might call the original raise. Say 4 players would call the CO's raise, but when the KJ reraises, it might make 0 of them call, so KJ gets to go heads up. When you think you're hand is strong u dont want hands like 10 J suitewd and whatnot calling on speculative draws. A perfect example is that AA is the best hand preflop, but if all ten players see a flop, there's a high likelihood someone will outdraw. If AA raises to isolate one or two players, the odds of him getting outdrawn are much less.