The only roles that can be deleted are created or cloned roles. System-provided roles (Administrator, Everyone, Registered Users) can't be deleted.
Use caution when deleting a role since you can leave a user with no permissions.
To delete a site role:
- Navigate to Control Panel > System Administration > Membership Administration > Members and Roles > Manage Site roles.
- Select the role you want to remove from the site in the Site Role drop-down list.
- Click Delete.
- Click OK in the confirmation dialog box. The role is removed from the Site Roles drop-down list.