As a default, past dates are removed and date ranges are changed to the upcoming event day. I want old dates to stay and date ranges to stay as they are. How and where do I modify the php? In simple event>the folder is add event>the file is site.php which shows the html, but I don't know where to change the php:

<div id="start_date">
<b>Date:</b> <?php echo date('F j, Y', strtotime($sdt)) ; ?>
</div>
<div id="datespan">
<?php
if ($edt > $sdt){
if ($eurotime==1){
echo date('Y/m/d', strtotime($sdt)).' - '.date('Y/m/d', strtotime($edt)) ;
}else{
echo date('m/d/Y', strtotime($sdt)).' - '.date('m/d/Y', strtotime($edt)) ;
}
}
?>
</div>