PassByValue vs PassByRerefence, C#

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//Rextester.Program.Main is the entry point for your code. Don't change it.
//Compiler version 4.0.30319.17929 for Microsoft (R) .NET Framework 4.5

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text.RegularExpressions;

namespace Rextester
{
    public class Program
    {
        public static void Main(string[] args)
        {
            var list = new List<int>();
            list.Add(1);
            list.Add(2);
            list.Add(3);
            
            Console.WriteLine("PassByValue");
            PassByValue(list);
            Print(list);
            
            Console.WriteLine("PassByReference");
            PassByReference(ref list);
            Print(list);
            
        }
        
        public static void Print(List<int> list)
        {
            foreach (var e in list)
            {
                Console.WriteLine(e);
            }
        }
        
        public static void PassByValue(List<int> list)
        {
            list = new List<int>();
            list.Add(3);
            list.Add(2);
            list.Add(1);
        }
        
        public static void PassByReference(ref List<int> list)
        {
            list = new List<int>();
            list.Add(6);
            list.Add(7);
            list.Add(8);
        }
    }
}

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Compilation time: 0,14 sec, absolute running time: 0,09 sec, cpu time: 0,08 sec, average memory usage: 13 Mb, average nr of threads: 3