HUM in return delivery

Hi All,

In HU managed storage location, I issued a normal delivery with 10 pallets of material doc #4900002731.

And then, one of the pallets should be returned, so I created a return delivery and placed the one pallet into the return delivery.

But, there are some errors as below;

So, I would like to know how to return pallet I posted before.

Thanks,

Khan