You remove users and\or domain groups from security roles when they are no longer applicable to the security role. When you remove a domain group and\or a user from a security group those users can no longer access the databases controlled by the security group.
Deleting Users from Security Roles
1. In the Alchemy Server console tree, expand Alchemy Server | <the node for your server’s name> | Security | Roles | <the target security role node>.
2. Click the Users node. The groups and individual users assigned to the security group appear in the details pane.
3. Right-click the group or individual user that you want to delete form the security role. Click Delete user\group on the shortcut menu.
When prompted, click Yes to confirm your action.