General answer: Expect not to be able to.
But as so often there will be hotels which will accept luggage from non guests for payment or even for free. The hard thing will be to find them.
In most of Europe the main cities will have luggage storage at the (main) railway stations, often also at smaller stations or in smaller towns and in those countries I do not expect hotels to publish they take luggage for non-guests.
In those countries where luggage lockers have disappeared you might find some hotels mentioning it or at least you getting directed to a hotel from the tourist information office, but do not expect that to be available in all places.
If you have status with a hotel chain you can try to call them, me not having status I can not tell you how your succes rate will be.