If you use the optional Production Manager module, you can create Production orders that do not need to be posted immediately. This allows you to work on a particular production and save work in progress, even when one or more component items are not fully available to complete production. When editing a production order, each component line has an indicator for the availability of quantity to use for production.
Component items with a red indicator do not have enough quantity on hand, those with a yellow indicator have enough quantity on hand but other production orders have some of that already committed, and those with an orange indicator do not have enough quantity on hand but a purchase order has already been issued for it.
When you click the Requisition button on the toolbar, the entire item list from the sales order is loaded into the Requisition work screen, with Required Quantities calculated from the respective component Remaining quantities and any quantity on hand, committed or on order.
From here, you can select just those items you want to requisition, and change quantities, costs or vendors for any item. Save all selections to the Requisitions list where the Required Qty is greater than zero. Or if you have user security rights, Process the items immediately into new Purchase Orders for each identified vendor.
If a subassembly component item does not have enough stock to complete production due to sub-components being short, and the subassembly is toggled to display sub-components, then the requisition will contain the sub-components to be processed into a Purchase order. If the subassembly is toggled to hide sub-components and there is not enough stock available, then the requisition will contain the subassembly item to be processed into another Production order.