Maintain Substitutions Associated Files MSS-4_Maintain_Substitutions_A_7-18-19.pdfMaintain SubstitutionsPDF • 416.66 KBDownload Details The purpose of this Business Process Procedure (BPP) is to explain how to maintain shift substitutions in the Integrated HR-Payroll System. BPP MSS-4. Last updated: Jul 18, 2019 First published: May 31, 2013