To exclude a built-in, source-specific Advanced Security Information Model (ASIM) parser from a built-in unified ASIM parser, you should create an analytic rule in the Microsoft Sentinel workspace. An analytic rule allows you to customize the behavior of the unified ASIM parser and exclude specific source-specific parsers from being used. Reference: https://docs.microsoft.com/en-us/azure/sentinel/analytics-create-analytic-rule