Permission levels on Box follow a "waterfall" design in which individuals have access only to the folder they are invited into and any subfolders beneath it. You can also be invited to individual files.
For example, if Kosh Naranek is invited to be a collaborator on the Box Reports parent folder, Kosh sees this folder and all subfolders (Design, Finance, Legal, and so on).
However, if Kosh is invited to be a collaborator in only the Marketing subfolder, Kosh sees only the Marketing, Approved, and In-Progress subfolders, but not the Design, Finance, and Legal subfolders.
If an individual is a collaborator on a parent folder, the access level is the same for all its subfolders. Changing permissions on the subfolder will result in an error being thrown. The collaboration is only changeable at the item which it was created. The system displays a message stating this information when changing someone's access level in a subfolder instead of in the parent folder.
For example, if Kosh is invited into the Box Reports parent folder as an Editor, you could not change Kosh's access to Viewer in the Marketing subfolder without changing Kosh's access to Viewer in the Box Reports parent folder as well. Changing Kosh's access to Viewer in the Marketing subfolder causes the access level to change to Viewer for the Box Reports folder and all its subfolders.
You can, however, give a collaborator a higher access level at a subfolder. To do this, first invite the collaborator to the subfolder, then invite the collaborator to the parent folder. For example, you could invite Kosh to the Marketing subfolder as an Co-Owner, then invite Kosh to the Box Reports parent folder as a Viewer.
In the All Files window's Sharing sidebar, Box displays your highest collaboration role. For other collaborators, Box displays the roles that were assigned to those collaborators when the collaborators were added to the folder. If any of these collaborators is a member of a group with higher access, Box does not dispay that higher role.
If you’d like to send a document to someone who is not a collaborator in the folder, use a shared link. The recipient of the shared link can preview or download the document.