Hi @rvnth ,
In query have targeting and filtering dimension as broad log schema. And in filtering condition, fetch the records you want to delete.
And After Query activity, use Update data activity and
select operation type as 'Delete',
Record identification: 'using reconciliation keys' and select primary key in destination and identifier.
Updated dimension: your broad log schema
(Before running the Workflow, disable update data activity and in Query's output transition make sure the results are same records as what you expect to get deleted and then execute 'Update data' to delete the records from Broad log)