Getting UserID from VisitorID

We set the UserID in our JS tracking code. From the reporting API I can only see VisitorID (e.g. Live.getLastVisitsDetails API). Is there a way to map the VisitorID to the UserID? We want to reach out to users who has experienced issues with our app.

Thanks,
Eric

I overlooked the API Live.getVisitorProfile(). Just need to call it with the VisitorID to get the UserID.