KSC Open API  13.0
Kaspersky Security Center API description
HostGroup::RemoveHost ( wstring  strHostName)

Removes the host record.

Parameters:
strHostName(wstring) host name. A unique string generated by the server (see KLHST_WKS_HOSTNAME attribute). It is not the same as computer network name, for example, DNS name, FQDN name, NetBIOS name.

See also how to use the KlAkOAPI Python package:

            server = KlAkOAPI.AdmServer.KlAkAdmServer.Create("https://ksc.example.com:13299", "username", "password", verify = False)
            oHostGroup = KlAkOAPI.HostGroup.KlAkHostGroup(server)
            # name of the host to remove
            strHostName = ...
            oHostGroup.RemoveHost(strHostName)