Generally running Mission Portal on alternative ports is currently an unsupported configuration. Be aware that updates to CFEngine are likely to revert your customizations.
To run Mission Portal on alternative ports both the httpd configuration as well as Mission Portal require modification.
To change the port the webserver listens on for http connections edit /var/cfengine/httpd/conf/httpd.conf and modify 'Listen 80' to whatever port you want. For the https you need to modify /var/cfengine/httpd/conf/extra/httpd-ssl.conf.
After these changes have been made you need to adjust /httpd/htdocs/application/controllers/settings.php changing $config['rest_server'] = $protocol . 'localhost' . '/api’; to $config['rest_server'] = $protocol . ‘localhost:<my new port number>' . '/api';.
Once the changes have been made simply restart cfengine.