For Reference type, Is there any symbol can represent that I don't want to change it?

Question

See the code, For Reference type, is there any symbol can represent I just want to pass the instance as a value? dont want to chang it

 internal class Program
    {
        static void Main(string[] args)
        {
            RefType refType = new();
            refType.Name = "Original name ";
            ChangeName(refType);//is there any symbol here can  represent that I don't 
									//want to change original instance
                                  //just want to us it? 
            Console.WriteLine(refType.Name);
        }

        static RefType ChangeName(RefType rt)
        {
            rt.Name = "name  changed";
            return rt;
        }
    }

    class RefType 
    {
        public string Name { get; set; }

    }

Answer 1

Maybe you can do something like this:

interface IReadonlyRefType
{
    public string Name { get; }

}

class RefType : IReadonlyRefType
{
    public string Name { get; set; }
}

static void Test1( RefType rt )
{
    rt.Name = "name  changed"; // OK
}

static void Test2( IReadonlyRefType rt )
{
    string n = rt.Name; // OK

    //rt.Name = "name  changed"; // Error
}

// Usage:
RefType refType = new();
refType.Name = "Original name ";
Test1(refType);
Test2(refType);

Answer 2

You can't change it where you indicate, but you could change:
class RefType

to

struct RefType