Split shipment is not available after reopening.
All newly placed orders will be single shipment. It is also not possible to change a placed order to split shipment.
Additionally please keep in mind that all English wave 1 items (like core boxes) that will be added now to an existing split shipment order will be sent in the second wave! We will not be doing a additional shipment between waves! 
If you wish to add a new pledge to your existing split shipment order we recommend creating a new order entirely to avoid additional shipping charges.