How to overwrite the core file to remove the timezone from the print to pdf file, How can we do this through the customization?

How to overwrite the core file to remove the timezone from the print to pdf file, How can we do this through the customization?

Path: sugar\modules\Reports\sugarpdf\sugarpdf.reports.php

Code :  $this->SetHeaderData(PDF_SMALL_HEADER_LOGO, PDF_SMALL_HEADER_LOGO_WIDTH, $this->bean->name, $timedate->getNow(true)"));

$timedate->getNow(true) instead of this we need to replace "date("D M j G:i:s")