Allow changing the product that is assigned to a live loan account.
Loans with long terms such as mortgages (20-30 years) can vary quite drastically over their term. Such variations which are in effect parameter changes (including interest calculation, accounting parameters etc.) to the account should not cause a rescheduling of the loan account to maintain continuous history and account statements for the loan account.
Therefore instead of baking more features into a single product so that account rescheduling is not required, it would be better to be able to change the parameters that apply to a given loan account by being able to change the product of an account.