- strftime: documentation ( source)
- strtotime: documentation ( source)
- ucfirst: documentation ( source)
<?php
$start_string = 'apr 6, 2019';
$end_string = 'mar 16, 2019';
$startdate=ucfirst(strftime ( "%e %h, %Y", strtotime($start_string)));
$enddate= ucfirst(strftime ( "%e %h, %Y", strtotime($end_string)));
echo "$startdate - $enddate";