Yes, but only if you travel strictly according to the itinerary.

For example, you bought a ticket with the itinerary St. Petersburg — Moscow — Milan — Moscow. You can fly from St. Petersburg to Moscow, then to Milan and not return to Moscow. But you cannot start your trip in Moscow, as you did not check in in St. Petersburg, and in such a case, the airline will cancel the entire ticket.

Please note that refunds for unused segments of the itinerary are made according to the fare rules. If the one-way fare is higher than or equal to the round-trip fare, no money will be refunded.