https://userapps.support.sap.com/sap/support/knowledge/en/3047881
3047881 - Error Message Function Module SD_PARTNER_SINGLE_MODIFY With Return Code 1 Completed | SAP...
You are replicating contracts to your S/4 Hana System and receive the following Error: "Function module SD_PARTNER_SINGLE_MODIFY with return code 1 completed"