Hi Anita,

There are two ways:

1. You may have separate view file for pdf export, for example MyReportPDF.view.php like we do in our example. The view file that use to export to PDF will not contain button. I personally prefer this way.
2. You can use parameters. Set a report parameter name "exportMode" that received boolean value. If the "exportMode" is true then you hide the Export button. You can access this parameter through $this->params["exportMode"] in the view file. With this way, the export function of your will look like this:

$report = new MyReport(array(
    "exportMode"=>true,
));

$report->run()->export()->pdf()->toBrowser("myreport.pdf");