How do we transition from our existing fiat monetary system to a registry based monetary system?

First, we introduce a basic income with fiat currency, funded by either taxes or membership fees.

We then annotate that currency as charge, and use it as such.  Since currency converts, you never actually lose it.

At any time, you can take your charge, value or exchange and use it in the fiat market if you have to.  However, it becomes lost at that point.

Any fiat currency that enters the registry system over and above the taxes or membership fees can only purchase transient exchange or value, which removes the fiat currency from the market (as the registrar will hold onto it and use it for the basic income).