Using Effectful Services in Non-Effectful Parts of an App

Maybe a dumb question - but in an incremental migration to effect in an app with existing services that are just plain TS classes, lets say I convert an service to an effectful service/layer.

But I may still need to use this service in "non-effectful" parts of my app. How could I get an instance of this service in those cases? Or maybe this is going about it the wrong way, not sure.