How can make this shader transparent by script?

I am currently developing a kinect game in unity using the package "KinectForWindows_UnityPro". In this package there is a premade greenscreen with shader called "GreenScreenShader". My goal is to just see myself but right now I see myself with a green background. Is there a way to make the shader transparent or should I use another method?

Shader "DX11/GreenScreenShader" {
SubShader {
Pass {

CGPROGRAM
#pragma target 5.0

#pragma vertex vert
#pragma fragment frag

#include "UnityCG.cginc"

UNITY_DECLARE_TEX2D(_MainTex);

sampler SampleType;

struct vs_input {
    float4 pos : POSITION;
    float2 tex : TEXCOORD0;
};

StructuredBuffer<float2> depthCoordinates;
StructuredBuffer<float> bodyIndexBuffer;

struct ps_input {
    float4 pos : SV_POSITION;
    float2 tex : TEXCOORD0;
};

ps_input vert (vs_input v)
{
    ps_input o;
    o.pos = UnityObjectToClipPos (v.pos);
    o.tex = v.tex;
    // Flip x texture coordinate to mimic mirror.
    o.tex.x = 1 - v.tex.x;
    return o;
}

float4 frag (ps_input i, in uint id : SV_InstanceID) : COLOR
{
    float4 o;
    
    int colorWidth = (int)(i.tex.x * (float)1920);
    int colorHeight = (int)(i.tex.y * (float)1080);
    int colorTransparency = (int)
    int colorIndex = (int)(colorWidth + colorHeight * (float)1920);
    
    o = float4(0, 1, 0, 0);
    
    if ((!isinf(depthCoordinates[colorIndex].x) && !isnan(depthCoordinates[colorIndex].x) && depthCoordinates[colorIndex].x != 0) || 
        !isinf(depthCoordinates[colorIndex].y) && !isnan(depthCoordinates[colorIndex].y) && depthCoordinates[colorIndex].y != 0)
    {
        // We have valid depth data coordinates from our coordinate mapper.  Find player mask from corresponding depth points.
        float player = bodyIndexBuffer[(int)depthCoordinates[colorIndex].x + (int)(depthCoordinates[colorIndex].y * 512)];
        if (player != 255)
        {
            o = UNITY_SAMPLE_TEX2D(_MainTex, i.tex);
        }
    }
    
    return o;
}

ENDCG

}
}

Fallback Off
}