如何使用three.js在框几何中编辑网格的顶点？

Question

如果我有一个立方体，那么我该如何改变它的顶点：

var material = new THREE.MeshBasicMaterial( {color: 0xce8b11, transparent: true} );
var geometry = new THREE.BoxGeometry( 200, 400, 20 );
var cube = new THREE.Mesh( geometry, material );
cube.position.x = 300;
cube.position.y = 300;
scene.add( cube );