modX::sendError
Send the user to a type-specific core error page and halt PHP execution.
The parameter 'type' can be any field, which will load the template file in core/error. MODx comes prepackaged with 2 default error pages; these are 'unavailable' (the default), and 'fatal'.
Syntax
API Doc: http://api.modxcms.com/modx/modX.html#sendError
void sendError ([string $type = ''], [array $options = array()])
Examples
Send an Unavailable 503 error page.
$modx->sendError('unavailable');
Send a Fatal 500 error page.
$modx->sendError('fatal');