On the Administration menu, select Access, then select Menu Access.
Expand a menu or menu item to see the roles that have been assigned to it:
To remove a role from a single menu node (e.g. a report), click the red directly next to the role, under the menu node.
To remove a role from an entire menu (e.g. all reports under that menu), click the red next to the menu header; all access will be removed beneath it.