how to remove last 3 characters from string in c#

string Name = "Teste,"
string ReturnName = "";
ReturnName = Name.Remove(Name.Length - 1);

myString = myString.Substring(0, myString.Length-3);

public static string ReplaceLastOccurrence(string Source, string Find, string Replace)
{
        int place = Source.LastIndexOf(Find);

        if(place == -1)
           return Source;

        string result = Source.Remove(place, Find.Length).Insert(place, Replace);
        return result;
}