using System;

using Newtonsoft.Json.Linq;

public class Program

{

    public static void Main()

    {

        var json= @"[

    {

        'Code': 'Global Payroll',

        'Month1': 1,

        'Month2': 0,

        'Month3': 0,

        'Month4': null,

        'Month5': null,

        'Month6': null,

        'Month7': null,

        'Month8': null,

        'Month9': null,

        'Month10': null,

        'Month11': null,

        'Month12': null,

        'YTD': 1,

        'PercentOfTotal': '16.67%'

    },

    {

        'Code': 'GV Payroll',

        'Month1': 0,

        'Month2': 0,

        'Month3': 3,

        'Month4': null,

        'Month5': null,

        'Month6': null,

        'Month7': null,

        'Month8': null,

        'Month9': null,

        'Month10': null,

        'Month11': null,

        'Month12': null,

        'YTD': 3,

        'PercentOfTotal': '50.00%'

    }  

]";

        JArray ja = JArray.Parse(json);

        JObject jo = (JObject)ja[0];

        jo.Property("Month4").Remove();

        json = jo.ToString();

        json.Dump();

    }

}