function sp_remove_membership($usergroup_id, $user_id)
{
    spdb_query('DELETE FROM ' . SFMEMBERSHIPS . " WHERE user_id={$user_id} AND usergroup_id={$usergroup_id}");
    # reset auths and memberships for added user
    sp_reset_memberships($user_id);
    sp_reset_auths($user_id);
    sp_update_member_moderator_flag($user_id);
    return true;
}
            }
        }
    }
}
if ($action == 'del') {
    check_admin_referer('forum-adminform_memberdel', 'forum-adminform_memberdel');
    $usergroup_id = sp_esc_int($_GET['usergroupid']);
    $new_usergroup_id = $_GET['usergroup_id'];
    if (isset($_GET['dmid'])) {
        $user_id_list = array_unique($_GET['dmid']);
    }
    # make sure not moving to same user group
    if (!isset($user_id_list) || $usergroup_id == $new_usergroup_id) {
        die;
    }
    for ($x = $startNum; $x < $startNum + $batchNum; $x++) {
        if (isset($user_id_list[$x])) {
            $user_id = sp_esc_int($user_id_list[$x]);
            $success = spdb_query('DELETE FROM ' . SFMEMBERSHIPS . " WHERE user_id={$user_id} AND usergroup_id={$usergroup_id}");
            if ($new_usergroup_id != -1) {
                $success = sp_add_membership($new_usergroup_id, $user_id);
            }
            # reset auths and memberships for added user
            sp_reset_memberships($user_id);
            sp_reset_auths($user_id);
            # update mod flag
            sp_update_member_moderator_flag($user_id);
        }
    }
}
die;