The key to separating them is getting your magnezone to discharge excess electricity. This may sound harmful to your bisharp, but as your magnezone’s abilities are fueled by its electric charge, it’s a necessary step to drain its electrical reservoir. However, if you do it correctly, this can be a perfectly harmless (albeit somewhat uncomfortable) experience for your bisharp.
Most pokémon centers actually have machines set up to do just this, as many ailments that plague the average electric-type involve an overabundance of electricity. Likewise, all Nurse Joys are trained in connecting a grounding machine to an electric-type’s discharge points (in your magnezone’s case, its magnets) to safely channel electrical energy into the machine alone.
However, if you don’t have access to a pokémon center, you can find a grounding machine in any pokémart. It’s heavily important to connect the grounding wires securely to your pokémon before running it, and do so with a pair of rubber gloves, not your bare hands. From there on out, follow the grounding machine’s instructions exactly, as not doing so may risk injury to yourself or your pokémon.
If you don’t have access to a grounding machine, you can potentially create one yourself, although this method is far riskier. Wind a length of copper wire to the ends of each of your magnezone’s magnets. Twist wires connected to the same magnet (for example, two copper wires connected to the left magnet, two to the right, and so forth) and wind the free ends of each of the wires around a grounding rod (or a pipe of conductive metal). The next step is highly important: dig a hole at least three feet deep and bury the rod. This is your grounder, and it, well, quite literally needs to be grounded in order to channel electricity to a safe area. Do not bury your rod in wet or marshy ground, and do not perform this task if the ground has recently been dampened with rain. This will also cause injury or property damage.
Once you’ve buried the rod, stand on a non-conductive surface (rubber mats or concrete, for example) and have your bisharp do the same. Then—and only after you’ve secured both yourself and your bisharp—order your magnezone to use its strongest electrical attack, focusing mainly on the copper wires to ensure the energy is channeled out of its body. Have it continue to do this until its electrical attack is noticeably weaker. By then, its magnetism should be weakened just enough for bisharp to pull away on its own. Once free, have your magnezone cut off its attack and wait for a few minutes. Do not allow your bisharp or magnezone to move, and do not move yourself. After a few minutes have elapsed (allowing the remaining electrical charge to dissipate, carefully unwind your magnezone from its grounding rod using a pair of rubber gloves and recall it. Then, ensure your bisharp’s armor has demagnetized by allowing it to touch metal. If it’s shocked or if the metal is stuck to it, give it another piece of metal and allow it to continue discharging until its armor is neutralized. Then recall it as well.
Finish off by taking both pokémon to the nearest pokémon center and having them examined by a professional. Make it clear that they’ve undergone a magnetic incident to ensure that the Nurse Joy in charge does not release the two at the same time.
Good luck, anonymous!