Anyone could roll forward all the transactions again, so you need to do more than just roll back. You need to declare the transactions invalid somehow. And unl

Anyone could roll forward all the transactions again, so you need to do more than just roll back. You need to declare the transactions invalid somehow. And unless every participant is in on it, you will end up with two cryptocurrencies afterwards. Holdings won't match on both chains. Find an exchange that is not running the same chain as you and spend a transaction that is valid on his chain but not the other, and by transferring out other cryptos you could empty their wallet.