Releasing an Order
1. From the Maintenance Processing screen, select the order you want to release with Orders ® Change. 2. From the header data screen or the operation overview, choose Order ® Functions ® Release. 3. Save the order.
Note If you have released an order to be performed, and subsequently enter additional operations for it, these are automatically released.
So this comes from the SAP website. As far as I understand you can NOT release operations only orders. If an order is released the operations are automatically released (ALL OF THEM)
Check the documentation: