How to reconfigure ionicBootstrap?

Ionic Framework ionic-v3
1

Hi,
how to handle refresh of token ?
once app is loaded I can configure token using

ionicBootstrap(MyApp,[
    HTTP_PROVIDERS,
    provide(RequestOptions, { useClass: DfRequestOptions })
    ],{
  pageTransition: 'ios',
});

DfRequestOptions returns the BaseRequestOptions for http access.
but how to reconfigure once app is loaded ?

ill check if token is expired then refresh it but dont know how to reconfigure ionicBootstrap with new token