Returning Unused Licenses 
You can return licenses that are no longer in use to SAP by posting a new request in the SAP Service Marketplace.
Procedure
1. In the internet address service.sap.com/licensekey, choose SAP Solutions for SMB.
2. Choose Request License Key, and then the corresponding installation number.
3. Choose the icon next to the system you want to change.
4. In the following screen, modify the number of users in the appropriate field.
5. Choose Submit to post the request.
You will receive a new license key file from SAP.
6. Import the new file.
See also
Importing a New License Key File