I think that's actually impossible. I often try to check my confirmation bias, I can make myself consciously aware of it, but I can't undo it. Like an optical illusion, you can't unsee it. Like riding the bike, you can't unlearn it.
I've had this experience recently with a video game: played for a decade, switched to another game for a few months, moved back to first game - unlearned the controls (instinct is to use controls of second game). Interestingly now I've re-learned my ability seems to have improved.
I think it works with optical illusions too: sort term as well, if my kids are anything to go by (they might have misreported seeing the illusion - eg lady in hat|hag with big nose).
N=1~, but across various activities. I'm a bit older, so brain plasticity is not what it used to be.