$re = '/^(.*?(\bdocbox\b.*.pdf).+)$/m';
$str = 'Failed to move from wasbs:///docbox/7391167/26988/service_report/EDINBURGH CLINIC LTD_999002225876_20121019.pdf/2022-02-07 18:53:41.pdf to wasbs:///docbox/7391167/26988/service_report/2022-02-07 18:53:41/EDINBURGH CLINIC LTD_999002225876_20121019.pdf';
$subst = "";
$result = preg_replace($re, $subst, $str);
echo "The result of the substitution is ".$result;
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