If you have a Self Invest Accumulation account, you can transfer the money you have in Self Invest to a Retirement Income account. You don't need to sell your portfolio or break the investments you hold in Self Invest. Because the investments are transferred, rather than sold, there's no capital gains tax to pay. You can then continue to invest in shares, ETFs, and term deposits from your Retirement Income account.
Keep in mind that if you transfer funds from a Retirement Income account to an Accumulation account, you'll need to sell your investments. If you decide to move everything over and sell all of your investments, you also need to close the Self Invest option.