Once the loyalty drops low enough, and the local militia feels stronger than the garrison, it's independence time. Many things dictate the loyalty and security of a settlement, like whether it was captured, garrison strength, potential culture mismatch between owner and inhabitants, etc.
Mount & Blade 2: Bannerlord players will be getting rebellions in the next beta patch, where unhappy citizens can rise up and take control of settlements. Similarly, when playing as a vassal, you will have the option to relinquish control of a fief back to the kingdom', TaleWorlds wrote.
' When playing as a faction leader, you will be given the option to grant fiefs to your vassals, allowing you to diversify the ownership of fiefs across your kingdom, or bolster relations with a clan that might not be too fond of your rule. The developer update is a hefty one, and it kicks off with the ability to grant and relinquish fiefs.