Regex Help

Could someone show me how to use preg_replace to change this: test <OPTION VALUE="test">test</OPTION> test into: anotherword <OPTION VALUE=\"test\">test</OPTION> anotherword basically, I want to change a value only if it is not in an option tag..... I also want to account for situations like : test, something <OPTION VALUE="test">test</OPTION> test! My thoughts were to do the replace if the word (test) was not surrounded by quotes or surrounded by greater/less than symbols. I just have no idea how to formulate that with regex. Please help! Thanks.