$re = '/(?<=(xyz)).*(?=Migrated)/m';
$str = '"Open Sole Student account (abc) 7 September 1999Converted to Graduate account (abc) 1 July 2002Converted to Student account (abc) 8 August 2002Converted to Advantage silver account (xyz) 4 November 2009Migrated to Select gold account (xyz) 24 July 2015”';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php