Edit lineTo points (in canvas)

Question

I want to move lineTo points.
How to do it?
I'm new to Canvas.
I'll give an example with Path.

This is my example:

var c = document.getElementById("myCanvas");
var ctx = c.getContext("2d");
ctx.beginPath();
ctx.moveTo(20, 20);
var line = ctx.lineTo(300, 100);
ctx.lineTo(70, 100);
ctx.lineTo(20, 20);
ctx.fillStyle = "red";
ctx.fill();
setTimeout(function() {
  /*
            I want something like this:
            line.editpoints(300, 150);
            */
}, 3000);

<canvas id="myCanvas" width="300" height="150" style="border:1px solid #d3d3d3;"></canvas>