Each piece is not a separate dataset as far as the catalog is concerned.
Ideally you are SMS managed so the politically correct answer is what you call
reorg the entire file. I understand that to be just copy to a new name and then
you can delete the current and rename the new to current.
Now if you want to play with fire, list the catalog entry so you know exactly
what order the pieces are in, uncatalog the dataset, move the piece on the
volume you want moved, and then catalog the dataset back again using the new
volser for the piece you moved.
