With the help of SAP Business ByDesign Business Scenarios Supplier Returns Management, you can send warehouse products back to your supplier.

Note the following when working with externally managed warehouses:
To use the scenario for logistics service processing, an add-on for warehouse service provider communication must be licensed via the SAP store. Note that the license of the add-on for warehouse service provider communication may incur additional costs.

The Create and Prepare Supplier Returns business process enables you to return damaged or unwanted products to the supplier using either a standard procurement process or a third-party order processing process.

The Process Outbound Delivery – Without Task Management business process is relevant for companies that prefer to process shipping proposals quickly and do not need system support in managing their warehouse processes and warehouse tasks. As soon as the outbound delivery has been created and released, the system posts the goods issue.

The business process Process Supplier Invoices gives you, the accountant, the option of entering invoices, credit memos and down payment requests that you have received from your supplier by fax or e-mail into the system, and checking and posting them there. Alternatively, the supplier, who can also be an affiliated company, can send you these documents electronically in the form of XML messages. With an automated invoicing process, all supplier invoices are compared with the associated purchasing documents, if available.
You can also bill the partner companies for supplier invoice items, and you can distribute incidental costs, such as freight costs, to all other supplier invoice lines. When the supplier invoice is complete and correct, you can post it. It is then used to pay the suppliers. If necessary, the system also creates new attachments automatically.

The Process Payables and Payments business process enables you to process outgoing payments that have been initiated either internally by your company or externally by your suppliers.
Payments can be made manually or automatically during a payment run in which the system proposes open items for payment. You then release the payments, whereupon they are posted by the system in accounting. You create the payment medium either manually or as part of an automatic run. The standard work center offers you checks, outgoing transfers and credit memos, as well as other country-specific payment methods. As soon as the payments have been debited from the bank account, the bank statement is recorded in the system. It is uploaded electronically or entered manually and then confirmed. If payments are initiated externally, the bank statement informs you that a payment has been made. The payments are matched with the open invoices in the system before they are cleared.

Source: help.sap.com, as of March 2017