Swap characters in a string

string input = "AXBYCZ";
char[] output = input.ToCharArray();

for (int lo = 0, hi = 1; hi < output.Length; lo += 2, hi += 2)
{
  output[lo] = (char)(output[lo] ^ output[hi]);
  output[hi] = (char)(output[lo] ^ output[hi]);
  output[lo] = (char)(output[lo] ^ output[hi]);
}

Console.WriteLine(new string(output));