After the 1-year anniversary a person can appeal the ban. WDW will review the situation and rule. If they rule against lifting the ban the person can appeal again in a year. I know this from Adam the Woo, a
YouTube personality who was banned for going and filming backstage on several occasions. He appealed twice, both times being rejected. An acquaintance of his was a lawyer in Florida who had a decent relationship with the Disney company offered to write a letter on his behalf for the next appeal, and WDW did lift it.
I have no idea how often this happens. Keep in mind this was a trespassing ban, there was no violence or theft involved. I imagine it would be even more difficult if that had been the situation. Best of luck, but the odds are not great and will likely take many years if it happens at all.