You have specified a stacked volume name using the CONTAINER operand of RMM CHANGEVOLUME subcommand. DFSMSrmm validity checking ensures that the volume has previously been exported to the specified stacked volume and that the copy on the stacked volume is still valid. DFSMSrmm validity checking uses values internal to DFSMSrmm in the form of an export token that is created when the original export was performed. DFSMSrmm also checks the name of the volume's previous stacked volume container and if the stacked volume is export recorded. If the stacked volume or exporting volume has been written to since the original export, DFSMSrmm resets the validation values to prevent virtual export.