STEPS TO REPRODUCE:
Migrate SRDs that already exist on target server using Deployment Management Console

ACTUAL RESULTS:
Getting error "Error: ARMigratePlugin: failed to validate SRM data: return code 30 return message " and deployment is stopped

EXPECTED RESULTS:
As per document merge should work with this tool

ADDITIONAL INFO: 

Error message in Deployment Manager: Error: ARMigratePlugin: failed to validate SRM data: return code 30 return message 

Error Type: Warning
Error Description: :Imported PDT skipped.
Solution: The import process has encountered a warning. The imported PDT has been skipped because it has the same values of unique indexes as an existing PDT. (Generic - Create Work Order) 

Error Type: Error
Error Description: :Imported AOT duplicates an existing AOT.
Solution: The import process has terminated because the imported AOT has the same name, company and locale an existing AOT. In order to resolve the conflict, the system used the provided prefix to change the AOT name. The name prefix provided will not result in a unique AOT name. To import, enter a different prefix to be added to the imported AOT name. Then run the import again. (Generic - Create Work Order) 

Error Type: Error
Error Description: :000000000000197
Solution: Validate: Validation of staged data has completed with errors. Cannot continue with import without changing import options.