When we say 're-registration' of assets (sometimes called 'in specie' or 'stock transfer') it means the process of transferring funds or shares to a different platform without selling the underlying investment.
Your holdings will be 're-registered' with the platform of the new company you have chosen to administer your investments. There will be a change of nominee account, but you remain the beneficial owner of the assets.
During the transfer, there will be a period when you won’t be able to sell your existing investments.
At Octopus Money, we can only facilitate 'in-specie' transfers out to your new provider, but all transfers in must be made in cash (so of course it means we can transfer in-specie to your Octopus Money account).