EndNote makes it very easy to edit existing citation styles.
If you need a style that isn't listed in the Style Manager, simply click on Get More on the Web.
EndNote offers three sets of defined term lists:
Think of these lists as controlled vocabularies or stored terms. It allows for consistent and standardized metadata across your entire EndNote Library. As you import citations into EndNote, it will automatically begin to populate these lists.
One of the most useful lists is the Journals Term List. This allows for a standardized list of full or abbreviated journal names, consistent with the citation style you're using, to be used in your final bibliography. You can download a full journal term list here.