Hello Giuliano Caetano,
What kind of error do you see in your console when you try to remove the userrole from the user, or do you want to know more about the process?
What can help is the following :
User management property of userroles
https://docs.mendix.com/refguide/user-roles/#user-management
Change members:
https://docs.mendix.com/refguide/change-object/#change-members
Hope this helps,
Good luck!
The roles are associated to the user.
What you need to do is remove the role(s) from the association.
In a MF you can retrieve the User and the UserRole you want to remove for this user. You can then simply change the user and update the association.
In the example below, you can see how to remove one specific rule