On the whole, italian part-time hours are fixed. Like fixed. This is to allow people to go to a second, or third, job on time. You can request they change ie come in early, stay later but no is backed up by law. Elastic clauses (contracts) exist, but the employer oays a hefty premium, and even then can only request a certain number/ percentage of hours are 'extra'. All this is for legal employment,as opposed to cash-in-hand jobs.