```php

// Before calling this method the creator of the PDF is identified as 'Factur-X library 1.x.x by HorstOeko'.
// After calling this method you get 'MyERPSolution 1.0 / Factur-X PHP library 1.x.x by HorstOeko' as the creator

$zugferdDocumentPdfBuilder = ZugferdDocumentPdfBuilder::fromPdfFile($zugferdDocumentBuilder, '/tmp/existingprintlayout.pdf');
$zugferdDocumentPdfBuilder->setAdditionalCreatorTool('MyERPSolution 1.0');
$zugferdDocumentPdfBuilder->generateDocument();
$zugferdDocumentPdfBuilder->saveDocument('/tmp/merged.pdf');

```