In Italy, if you need to exchange a large banknote for smaller bills without making a purchase, you should politely say: "Scusi, ha da cambiare [amount]?" (Excuse me, do you have change for [amount]?). For example, if you have a 50 Euro bill and want smaller ones, you would say, "Scusi, ha da cambiare cinquanta euro?" If you have already made a purchase and want to ask for specific change, you can use the word "resto" (change). For a more specific request, like asking for two 10s and a 5 for a 25 Euro balance, you could say: "Potrei avere banconote più piccole, per favore?" (Could I have smaller bills, please?). It is common to ask this at "Tabacchi" shops or newsstands, though many small vendors may be reluctant to give up their small bills unless you buy something. In a formal setting like a bank, you would say: "Vorrei cambiare questa banconota in pezzi più piccoli" (I would like to change this bill into smaller pieces).