@Heavysnack It can vary a bit by type of co-op, but generally to become a #coop member one purchases a share that is not connected to the market value of the form, so it could be token (my credit union is $25) or significant (the highest #WorkerCoop share price in Vermont is $15k).
So, to off board a member, that share is bought back at face value, and the member is also paid any retained patronage that has been accumulated in their internal capital account.