There is exactly this situation (not too scientifically handled) in an old episode of Space:1999 ("Matter of Life and Death"), where the transformation was caused by "an unknown form of radiation".
More to the point, this is also done in Anvil of Stars by Ben BovaGreg Bear, where Benefactoralien technology allows to "reprogram" particles - alter their quantum state at a distance, changing their very nature. In the book, quarks and leptons are mostly always the same particle, their difference in charge and Higgs mass arising only by their state vector (this is a real thing in physics, you may want to look up Bohm's hypotheses). While it does take energy to flip a particle's vector state's bit by hijacking its entanglement channel (the book calls it no-ach), if you do so, you change that particle into something else - if you change a particle into a particle that existed elsewhere, that's the "classic" quantum teleportation. This solution could work for you.
(Of course, not only the general form of quantum manipulation is completely hypothetical; even the classic quantum teleportation hasn't been conclusively proven, and even if it was, it wouldn't be exactly what you need. But the description does come close).