Are you serious? Different blockchains mean different code, different framework and structure, different processes. You cannot just freely switch between them and keep your same address. Someone has to audit the ERC20 coins and do the swap at the agreed upon rate to verify and validate all holders’ coins. If you could, then I guess ETH, Icon, EOS, Bitcoin Cash, Tron, VeChain, NEO, etc all wasted a lot of time and resources doing token swaps.

Please tell me, if you can keep your same address, and the token can exist on two blockchains at one time, then when you send funds to the address, which blockchain would your funds go to? How does this work?