How do I migrate employee data from multiple regional spreadsheets into one HRIS without losing historical leave balances?

Omni HR's migration process includes data auditing and employee record import from Excel or legacy systems, handled by a dedicated Customer Success Manager, so historical leave balances from multiple regional spreadsheets get consolidated into one employee database instead of reset to zero at go-live. A parallel run before cutover confirms the imported balances match each region's original records before the new system takes over.