How can we modify Anchor transform values in realtime in arkit

I am able to track body motion using Arkit. In the session function on anchor update I get the anchor values. I need to update the anchor transform values in realtime so that the usdz shows the motion that I program and not the human tracked motion. How can we achieve this. The session function is below

func session(_ session: ARSession, didUpdate anchors: [ARAnchor]) {

        for anchor in anchors {

            guard let bodyAnchor = anchor as? ARBodyAnchor else { continue }
            let hipWorldPosition = bodyAnchor.transform
            let skeleton = bodyAnchor.skeleton
            let jointTransforms = skeleton.jointModelTransforms
            for (i, jointTransform) in jointTransforms.enumerated() {
                let parentIndex = skeleton.definition.parentIndices[i]
                guard parentIndex != -1 else {continue}
                let parentJointTransform = jointTransforms[parentIndex]
            }
            // Update the position of the character anchor's position.

            let bodyPosition = simd_make_float3(bodyAnchor.transform.columns.3)

            characterAnchor.position = bodyPosition + characterOffset

            // Also copy over the rotation of the body anchor, because the skeleton's pose

            // in the world is relative to the body anchor's rotation.

            characterAnchor.orientation = Transform(matrix: bodyAnchor.transform).rotation

            if let character = character, character.parent == nil {
                characterAnchor.addChild(character)
                //characterAnchor1.addChild(character1!)
            }
        }
    }