how to call a function on the main timeline from a nested timeline

Hi Animate Support,

I'm using JavaScript in Canvas and I am trying to find a way to call a function on a movie clip on the main timeline from a movie clip in a nested timeline.  This is important because of the way the graphics work in my FLA.  Here's my code on the main timeline:

let bellFrontLt = this.bellFrontLt_mc; 

function positionBellFrontLt()
{
	bellFrontLt.x = 200;
	bellFrontLt.y = 100;
	alert("move bell flower")
}

The name of the nested movie clip is all_clip which holds the movie clip (functioning as a button), bellFrontLt_btn.  Neither of the commented-out commands below worked.  Here's my code on the nested clip: 

this.bellFrontLt_btn.addEventListener("click", callFunctionMainTimeline.bind(this));

function callFunctionMainTimeline()
{
	//this.parent.positionBellFrontLt();
	//exportRoot.positionBellFrontLt();	
}

Any help finding a way to do this will be greatly appreciated.

Zaffer