VMS Help SET, SECURITY, Qualifiers, /OWNER  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /OWNER=identifier

    Requires GRPPRV (group privilege) to set the owner to another
    member of the same group. Requires SYSPRV (system privilege) to
    set the owner to any user identification code (UIC) outside your
    group.

    Modifies the owner element of an object. Specify the user
    identification code (UIC) or general identifier in the standard
    format. Modifying the owner element of a file usually requires
    privileges. Refer to the OpenVMS Guide to System Security for
    more information.