Formatting a bibliography serves two functions:
It formats each in-text citation according to the selected bibliographic style.
It adds a complete bibliography to the document (unless you override this with a setting in the output style).
Instant Formatting actually works as you insert citations and is enabled when you first start using Cite While You Write. EndNote uses the currently selected style to format citations and update the bibliography each time a citation is inserted. However, if you want to change the style or layout of references, you can use the Format Bibliography tab from the Configure Bibliography dialog.
Configure Bibliography allows you to modify bibliography preferences such as style and layout before formatting your document. This is also where you enable or disable Instant Formatting.
From the Tools menu, select the EndNote submenu, and then select Configure Bibliography.
From the EndNote tab, in the Bibliography group, click the bottom corner arrow to open the Configure Bibliography dialog.
On the Format Bibliography tab, use the With Output Style option to select an output style to format references.
Click OK to format all citations and build the bibliography.