Normally warning letters, advise memos etc are signed by the employees' Head of Deptt., and
not HR staff/his immediate supervisor. For e.g. employees working in Production deptt., shall be signed by Manager-Production or Manufacturing Manager. In some companies, departments such as Production, QC, Maintenance, Production Planning & Control etc. - these departments have separate department managers - these persons are reporting to Manufacturing Manager, who is the overall Incharge of Manufacturing facilty/Shops. In such cases, Manufacturing manager is the competent authority for all disciplinary actions against Shop floor employees.