code: public void unregisterFromPushServices(final Respoke.TaskCompletionListener completionListener) {
          if (isConnected()) {
              SharedPreferences prefs = appContext.getSharedPreferences(appContext.getPackageName(), Context.MODE_PRIVATE);
  
              if (null != prefs) {
                  String lastKnownPushTokenID = prefs.getString(PROPERTY_LAST_VALID_PUSH_TOKEN_ID, "notAvailable");
  
                  if ((null != lastKnownPushTokenID) && !lastKnownPushTokenID.equals("notAvailable")) {
                      // A push token has previously been registered successfully
                      String httpURI = String.format("/v1/connections/%s/push-token/%s", localConnectionID, lastKnownPushTokenID);
                      signalingChannel.sendRESTMessage("delete", httpURI, null, new RespokeSignalingChannel.RESTListener() {
                          @Override
                          public void onSuccess(Object response) {
                              // Remove the push token ID from shared memory so that push may be registered again in the future
                              SharedPreferences prefs = appContext.getSharedPreferences(appContext.getPackageName(), Context.MODE_PRIVATE);
                              SharedPreferences.Editor editor = prefs.edit();
                              editor.remove(PROPERTY_LAST_VALID_PUSH_TOKEN_ID);
                              editor.apply();
  
                              Respoke.postTaskSuccess(completionListener);
                          }
  
                          @Override
                          public void onError(String errorMessage) {
                              Respoke.postTaskError(completionListener, "Error unregistering push service token: " + errorMessage);
                          }
                      });
                  } else {
                      Respoke.postTaskSuccess(completionListener);
                  }
              } else {
                  Respoke.postTaskError(completionListener, "Unable to access shared preferences to look for push token");
              }
          } else {
              Respoke.postTaskError(completionListener, "Can't complete request when not connected. Please reconnect!");
          }
      }
docs: Unregister this client from the push service so that no more notifications will be received for this endpoint ID
  
  @param completionListener  A listener to receive the notification on the success or failure of the asynchronous operation