Remove extra spaces (Space Character) from a sentence using C# .Net

How to remove whitespaces if it is more than 2. What i want to say is -

1. If there is one whitespace, its OK.

2. If there is two whitespace, its OK.

3. BUT, if there is more than two whitespace than replace them with only two whitespaces.

String may be like this :- (it may contain any character)

DuntaviDilaniyd.dilaniy@woridnitattnit                        15 jim alixandir id         PALESTINE      TX

48568 2470325837 US              FEMALESunday, April 09, 1939 162       170     A+      • Duntavia

Delaney           Jon Muller         Sherman                          TX        84321 US          9974766226 NO           NO       YES

NO        NO        Yt i7-Uri-11616               Sunday, April 09, 1939 $200.00      ' Duntavia Delaney

Sherrie Minter BaX OlaCp 9719               Sunday, April 09, 1939 FEMALEVisa     CLONAZAPAM 10

MG                   60                    $2.85 5171.00 $20.00 $191.00                       Not Available

public static string ConvertWhitespaceToSpaces(string value)
        {
            char[] arr = value.ToCharArray();
            for (int i = 0; i < arr.Length; i++)
            {
                switch (arr[i])
                {
                    case '\t':
                    case '\r':
                    case '\n':
                    case ' ':
                        {
                            arr[i] = ' ';
                            break;
                        }
                }
            }
            return new string(arr);
        }

I did this but it doesn't work as per my need.

I did this too :--

List<string> splitStrings = str.Split(new[] { "  " }, StringSplitOptions.RemoveEmptyEntries).Select(s => s.Trim()).ToList();
string[] words = splitStrings.ToArray();