code: public void initiateConference(String connId, String destination) throws WorkspaceApiException {
          this.initiateConference(connId, destination, null, null, null, null, null);
      }
docs: Initiate a two-step conference to the specified destination. This places the existing call on
  hold and creates a new call in the dialing state (step 1). After initiating the conference you can use
  `completeConference()` to complete the conference and bring all parties into the same call (step 2).
  @param connId The connection ID of the call to start the conference from. This call will be placed on hold.
  @param destination The number to be dialed.