My FOIL request has been rejected, can i file a appeal?
That rejection has been for a whole or only for a part of your request?
It was for a part on the information requested, yes.
You may indeed appeal the rejection then. You must proceed writing before 30 days from the date of denial for your FOIL request. It must contain a description of the contents which were rejected and have your appeal identified with the date of your record request.