Yes, they can. There's a reason that college "turns kids liberal." It's because meeting people from various cultures and backgrounds and learning that they're just people too does a lot to combat the indoctrination they experienced.
Many of these people literally don't know any better because they've been lied to their whole lives. Critical thinking and questioning authority is actively punished. The media that they were raised on trained them to think that any other source is lying to them.
It takes work, sometimes a lot of it, but most people can be reached. I've personally helped several people, even converting a "god put dinosaur bones in the ground 6k years ago to test us" believer.
But saying every conservative is a sociopath incapable of change just shows that you lack the ability to be empathetic. If there's absolutely no room for forgiveness, then what reason do they have to change?