Do I need to Rewrite Content for Landing Page

Lets say my site is about black cars, If i want to target the blue car market, I would make a landing page. Can I just replace the content on the landing page by removing the word black car whereever it shows up and replacing it with blue car. Or do I need to rewrite/reword all of the content.

I think by the fact that you had to ask that question, you already know the answer.

If you just replaced 1 word, then each site would be 99% duplicate content.

Just trying to make sure. I didnt know if there would be an exception to content that is on the same domain or not.