Changes in your organization can mean that you have to withdraw a role from a Windows login.
Click Tools, Security, Windows Logins and the Windows Logins window appears. Make sure that the current record symbol on the left side of the window is next to the login of the user from whom you want to withdraw this role.
Click Roles at the bottom of the window. The Windows Logins, window for this role appears. This window lists the roles that this user has been given.
Select the role you want to remove from this Windows login.
Press Delete.
Giving Roles to Database Logins
Giving Roles to Windows Logins
Removing Roles from Database Logins