What is manual migration of Excise module from Tally ERP 9 Release 5.2 onwards? In which scenario should it be done? What will be effect?

Data which are already migrated to 5.x releases will not get re-migrated automatically. If you want to re-migrate these rates from release 5.0 or 5.1 to release 5.2 and above manually, press Ctrl+Alt+M from Gateway of Tally, and choose the below options as required:

 Tax rate for VAT and Excise 

(it migrates tax rates for both Excise and VAT and this option will be available only if both Excise and VAT are activated for the company)

Excise 

(It migrates tax rates only for Excise)