Hello,
We recommend you to don't overwrite the template. Phpdocx doesn't change the original template unless you overwrite it.
For example, this code:
$docx = new CreateDocxFromTemplate('TemplateSimpleText.docx');
$first = 'PHPDocX';
$variables = array('FIRSTTEXT' => $first);
$docx->replaceVariableByText($variables, $options);
$docx->createDocx('output');
generates a new DOCX file, output.docx, without changing the template.
Regards.