Adapting OER means making changes to already existing open content (Revise and Remix). It can be as basic as editing the content so as to customize it to your needs (Revise) or finding other OER content that you can combine and integrate with the original OER content (Remix).
Adapting is really where the strength and beauty of OER comes into play because it allows you to tailor content to the specific needs of your course. The flexibility of revising and remixing OER will also provide an easy way for course content to remain up to date or be modified whenever faculty decide to make changes to their course objectives.