Changing React Native Debugging port

Question

I saw some questions question 1 and tutorial that describes how to change the packager running port. However, it's not clear to me how to change the listing port on native code.

I have an hybric application with a code like this

ReactInstanceManager.Builder builder = ReactInstanceManager.builder()
                .setApplication(application)
                .setDefaultHardwareBackBtnHandler(application.getGAMActivity())
                .setInitialLifecycleState(LifecycleState.RESUMED)
                .addPackage(new MainReactPackageWrapper())
                .setCurrentActivity((Activity) application.getGAMActivity())
                .addPackage(new StoreReactNativePackage())
                .addPackage(new ExceptionHandlerCustomPackage())
                .addPackage(new UtilsNativePackage(application))
                .addPackage(new SessionPackage(false, (Activity) application.getGAMActivity()))
                .addPackage(new MyCameraPackage())
                .addPackage(new RealmReactPackage())
                .addPackage(new FetchCustomPackage())
                .addPackage(new LocationServicesDialogBoxPackage())
                .addPackage(new RNDeviceInfo())
                .addPackage(new RCTPdfView())
                .addPackage(new MapsPackage())
                .addPackage(gamCommunicationReactPackage);

then

 if (isrunningonpackager) {
            builder.setUseDeveloperSupport(true);
            builder.setBundleAssetName("index.android.bundle");
            builder.setJSMainModuleName("index.android");
        } else {
            builder.setBundleAssetName(myApplication.getAppName().concat(LocalAppsFilesManager.APPLICATION_BUNDLE_EXTENSION));
            builder.setJSMainModuleName(myApplication.getAppName().concat(".bundle"));
            builder.setUseDeveloperSupport(false);
        }

How to I tell the builder to look for the packager on another port?