Creating Purchase Orders Directly from Sales Orders 
You received an order from one of your customers, and the ordered goods are not in stock. You want to create a purchase order directly from the sales order to buy the goods from a vendor.
Prerequisites
You are authorized to create both sales and purchase orders.
You have created a sales order that includes delivery from a drop-ship warehouse, or you have created a sales order according to the following procedure:
From the SAP Business One Main Menu, choose
Sales – A/R 
Sales Order 
.Specify the customer and item information as well as any billing or shipping information.
On the Logistics tab, select the Procurement Document checkbox.
This initiates the procurement confirmation wizard, which allows you to create a purchase order for the goods that are not in stock.
Procedure
Create a sales order as indicated above and choose Add.
The Procurement Confirmation Wizard appears. In the Customer window, the relevant customer is displayed and selected. If required, specify additional customers for whose sales orders you want to create purchase orders.
To be able to create purchase orders for all open sales orders with unfulfilled purchase quantities for the selected business partners, select the Include All Open Sales Orders checkbox. If you do not select this checkbox, the only sales orders displayed are those for which the Procurement Document option was checked on the Logistics tab of the sales order or that use a drop-ship warehouse and have unfulfilled purchase quantities.
Choose Next.
In the Sales Orders window, all open sales orders for the selected customers are displayed.
Select the sales order or sales orders for which you want to purchase items.
Choose Next.
The Sales Order Line Items window appears.
Select the target document type Purchase Order.
By default, the quantities for the selected items are the quantities from the sales order(s). If required, change the quantities for the purchase order.
If an item has a preferred vendor assigned to it, this vendor is already entered in the line. If required, change the vendor code.
For all items that do not have a vendor assigned to them yet, enter a vendor code.
To specify the same vendor for all items, enter the vendor code in the Vendor field of the wizard body.
To specify the vendor for each item individually, enter the vendor code in the Vendor or Vendor Name column of the table.
To save the purchase order as a draft, select the Create Draft Document checkbox.
Choose Next.
In the Consolidations window, specify whether to consolidate several sales orders into one purchase order and which consolidation options to apply.
To do the following:
Choose:
Create one purchase order per sales order
No Consolidation
The documents are grouped by vendor, that is, one purchase order is created per vendor.
Consolidate several sales orders into one purchase order
Consolidated by and select the relevant option:
Vendor (System Default)
The documents are grouped by vendor, that is, one purchase order is created per vendor. This setting cannot be changed.
Warehouse (Split)
The documents are grouped by the warehouse that is used to ship the items. That is, if items are sold from different warehouses, one purchase order is created per warehouse.
Other
You can specify additional grouping criteria, such as the delivery date or shipping type.
Specify the system response to errors that may occur in the document generation process. To do so, make a selection in the If an Error Occurs field and choose Next.
The Preview Results window appears. It displays all purchase orders that will be created grouped by vendor and the consolidations options you selected.
To generate the documents, choose Next.
The application creates the relevant documents and displays a summary report of all documents that were created and any errors that occurred.