code: public void mergeCalls(
              String connId,
              String otherConnId,
              KeyValueCollection reasons,
              KeyValueCollection extensions
      ) throws WorkspaceApiException {
          try {
              VoicecallsidmergeData mergeData = new VoicecallsidmergeData();
              mergeData.setOtherConnId(otherConnId);
              mergeData.setReasons(Util.toKVList(reasons));
              mergeData.setExtensions(Util.toKVList(extensions));
  
              MergeData data = new MergeData();
              data.data(mergeData);
  
              ApiSuccessResponse response = this.voiceApi.merge(connId, data);
              throwIfNotOk("mergeCalls", response);
          } catch (ApiException e) {
              throw new WorkspaceApiException("mergeCalls failed.", e);
          }
      }
docs: Merge the two specified calls.
  @param connId The connection ID of the first call to be merged.
  @param otherConnId The connection ID of the second call to be merged.
  @param reasons Information on causes for, and results of, actions taken by the user of the current DN. For details about reasons, refer to the [*Genesys Events and Models Reference Manual*](https://docs.genesys.com/Documentation/System/Current/GenEM/Reasons). (optional)
  @param extensions Media device/hardware reason codes and similar information. For details about extensions, refer to the [*Genesys Events and Models Reference Manual*](https://docs.genesys.com/Documentation/System/Current/GenEM/Extensions). (optional)