Purchase order Workflow Inactive , confirmation button hide

Dear fellows,

In inactivate my purchase workflow , after this my all previous open purchase orders 'Draft' do not go for confirm, because the button is disable . even all those open purchase orders which are already 'Approve' or 'Confirmed' after click 'Request change button' there is no edit option available but again Confirmation button is disable.

Only new created purchase orders are working fine.

Kindly confirm me how could i process my old purchase orders ?

Thanks

Sarfaraz Khan