NAS 516 Permission Problem

OS 6.7.4

Permissions are all messed up.  We were using Egnyte and have stopped synching with them.  Users can't access folders and files.  When I view the top folder security permissions under "data" with a Windows 7 laptop, I can see users who don't exist on the NAS as owners of the folders.  I want all users to have "Everyone" access to all folders and files.  How can I change permissions to rid of the old owners and have "Everyone" permissions?  Although I can see the permissions, I receive an error that I don't have privileges to access or make changes and to check with my administrator.  I'm not sure where to turn and can use any advice available.  Thank you in advance.

PS  I would really like to see Netgear add a "view" into the permissions on shares, like on a PC.