In Italy, a building amnesty (“condono edilizio”) and a building regularisation (“sanatoria edilizia”) are not the same thing, even though the terms are often used loosely and interchangeably.
A building amnesty (“condono”) refers to temporary legislation that allows unauthorised building works completed by a certain date to be legalised, by regularising them on payment of a fine. An amnesty therefore lets you legalise violations already committed, but it does not authorise new unauthorised works.
A building regularisation (“sanatoria”), on the other hand, refers to legalising works carried out without a building permit that nonetheless comply with the planning, landscape and health-and-hygiene rules set by law. In essence, a “sanatoria” regularises works done without a permit that still respect the planning and health rules in force.
In short: an amnesty is an extraordinary, time-limited measure that can cover works even where they don’t fully comply, while a “sanatoria” is the ordinary route and applies only to works that comply with the rules.
This article is for general information and refers to Italian law; for your specific property, always rely on a qualified technician or professional.