Authorities should look to reconsider cases where new information may change the outcome, for example, where a property is retrospectively listed as liable for council tax.
Dylai awdurdodau ailystyried achosion lle y gallai gwybodaeth newydd newid y canlyniad, er enghraifft, pan gaiff eiddo ei gofrestru'n ôl-weithredol fel un sy'n atebol i dalu'r dreth gyngor.