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

       /OWNER_UIC[=uic]

    Sets the owner user identification code (UIC) of the volume
    to the specified UIC. The default UIC is that of the current
    process. Brackets ([])  are required around the UIC. Specify
    the UIC by using standard UIC format as described in the OpenVMS
    Guide to System Security.