Changing the Heightmap of the Shader during rendering

I am using a 'Tessellation/Bumped Specular (displacment)' Shader and I want to change the heightmap during the rendering by C# code. I could not find a method to change the heightmap. I am a beginner... please give me some help by code.

Code (CSharp):

1. Shader tx = GetComponent<Renderer> ().sharedMaterial.shader as Shader;

At this moment my first frame looks like this... done by drag and drop.

 

Thanks. I am a total beginner in Unity. I have some experience in C#. Could you give me a small example to set/get the heightmap in the code?

 

@Jordi Bonastre It is not updating the heightmap. Do you see a mistake

Code (CSharp):

1. void Update () {
2.         if (vr_objects.Count () > 0) {
3.             int index = (int)(Time.time * 30);      
4.             index = index % vr_objects.Count ();
5.             if (index < vr_objects.Count ()) {
6.  
7.                 // Displacement map - not working                      
8.                 renderer.material.EnableKeyword ("_PARALLAXMAP");
9.                 renderer.material.SetTexture("_PARALLAXMAP", disp_tex[index]);
10.  
11.                 //Moving plane - works
12.                 Vector3 vec = new Vector3 (0, transform.position.y, (float) vr_objects[index].Rel_Position); // transform.position.z + 1);
13.                 transform.position = vec;
14.             }
15.         }
16.     }

 

Ahhh... Thanks @Jordi Bonastre

Code (CSharp):

1. renderer.material.EnableKeyword ("_PARALLAXMAP");
2.                 renderer.material.SetTexture("_ParallaxMap", disp_tex[index]);