<?php
$re = '/(\s"\S+"(?:\p{P}|\s))|"/';
$str = 'this i"s a "test" word i"s"s. NOt a "test".';
$subst = '$1';
echo $result;
PD9waHAKJHJlID0gJy8oXHMiXFMrIig/Olxwe1B9fFxzKSl8Ii8nOwokc3RyID0gJ3RoaXMgaSJzIGEgInRlc3QiIHdvcmQgaSJzInMuIE5PdCBhICJ0ZXN0Ii4nOwokc3Vic3QgPSAnJDEnOwoKJHJlc3VsdCA9IHByZWdfcmVwbGFjZSgkcmUsICRzdWJzdCwgJHN0cik7CgplY2hvICRyZXN1bHQ7