Transfer of Purchase Order Quantity to another Plant

Good Day Gurus,

I have this situation wherein a Purchase Order with Quantity of 50,000 kgs by Plant 1 has been released.

During Invoicing and GR, only 6,000 kgs were processed and thus a hanging balance of 44,000 kgs still exists.

The responsible buyer wants to transfer the remaining quantity of Purchase Order to Plant 2.

What are the possible solutions can be done to arrive with her request?

Thanks,

Harvey