Endnote + Brookings style

Unless you are using Online version thru an institution with an administrator, there is no way I know of apart from contacting Endnote Support to adjust an output style (and that is usually a lengthy process).   (More information and submission link to request a new style is in the [KB article here](/t5/forums/replypage/board-id/en-howto/message-id/24666/load-autosave/KB article here))

When looking at the Brooking style guide, it talks about two variants.  There are two or three variants of Chicago 16th (A is footnotes and bibliography, B is not Author, year, not footnote).  I guess A is more like Brooking footnote style requirements?  

You could modify a style or use a style modified by someone else for you  using the Desktop version of endnote (while for example using a trial version).  but that is an option for a very limited time, so you might want to wait until you are ready to submit.  Or find a friend or colleague who has the full desktop version to reformat it for you.