Manually invoking a Thing Service using Studio JavaScript

Hi Team!  In a Studio AR project, using scope commands at the AngularJS level, is there a way to manually execute a Service defined on a Thing?  Use case is having certain properties and/or input parameters change during an AR experience, and you need to re-run the Service and fetch new external data.

For example, I know you can manually play the current 3D sequence of a model widget by doing something like this:

angular.element(document.getElementById('model-1')).scope().play();

... which works fine. I also have seen examples on how to get data from a Thing Service using code like

var result = $scope.app.mdl['ThingName'].svc['servicename'] ;

...but I’m looking for a way to invoke and execute the service manually in code.  Aside from using the “Invoke On Entity Change” (doesn't seem to work in my scenario) and “Auto-refresh” configuration options that are available on Services (after adding the External Data entity in Studio), can you manually execute a Service using JS run-time commands?

Thanks!