You can delete any previously discovered network devices, computer, domain, service, or account by selecting it, then clicking Delete from the Actions drop-down list. If you manually delete a discovered object, however, the object will not be added to Privileged Access Service the next time you run a discovery job by default. Privileged Access Service handles the re-discovery of previously deleted systems, domains, services, or accounts differently. Previously deleted systems or accounts are listed on the Excluded Systems or Excluded Accounts page in Admin Portal > Discovery > Systems and Accounts > Excluded Systems or Excluded Accounts. If you want previously deleted systems or accounts to be re-discovered next time you run a discovery job, then remove those systems or accounts from the Excluded Systems or Excluded Accounts page.
If you accidentally delete a discovered domain, service, or account , you can manually add it to Privileged Access Service or run a discovery profile with the relevant Windows Services options selected and the New and existing systems option selected on the Actions page -- Admin Portal > Discovery > Systems and Accounts > Profiles > relevant profile > Actions. Domains, services, and accounts are tied to services or tasks, which are tied to systems. If you have not deleted the associated systems, then re-running a discovery job will re-discover those previously deleted domains, services, or accounts -- provided you have the relevant options selected on the Actions page. See Specifying systems discovery actions for more info on the actions.