Moving Tape drive between partitions on old 520

Hi,

I have an old Power5 model 520 that has a single tape drive, and two partitions.
I need to move the tape device from the first partition to the second, in order to do a system save to tape. (I'd love to use Virtual Tape on the second partition but it's a v5r3 partition and virtual tape wasn't supported until v5r4).
I can't remember how I did it before (some years ago) and can't find how to do it now. I do have the tape I did the last system save on so I know I did it somehow.
I think I have to remove the device from the first partition and add it to the second but I also have a recollection that I have to move the IOP it's attached to.
But the IOP it's attached to has everything on it, including all the disk drives. So, I can't move the IOP without crashing the first partition.

This box is used for development so shutting it down and reconfigures are OK.

Any direction suggestion?