Rule reminder
Italian legal and contractual language uses fixed exceptive formulas: 'salvo diversa indicazione' (unless otherwise indicated), 'salvo quanto diversamente previsto' (unless otherwise provided), 'fatte salve le disposizioni' (without prejudice to the provisions), 'salvo accordo contrario' (unless otherwise agreed), 'eccetto quanto previsto' (except as provided). These are nominal/participial structures — no subjunctive is needed as there is no finite verb.
Le modifiche al contratto devono essere in forma scritta, _____ quanto stabilito nel presente accordo.