code: public void deleteFromConference(String connId, String dnToDrop) throws WorkspaceApiException {
          this.deleteFromConference(connId, dnToDrop, null, null);
      }
docs: Delete the specified DN from the conference call. This operation can only be performed by the owner of the conference call.
  @param connId The connection ID of the conference.
  @param dnToDrop The DN of the party to drop from the conference.