"Step -1" means that for every loop, the integer 'i' will be decreased by 1 until such time that 'i' will be equal to 2.
For MyStr = Trim$(Replace(MyStr, Space(i), Space(1))) ... It means that all Space(i) string within the value of MyStr will be replaced by the string Space(1) and then the new string will be assigned to MyStr. Unless "Space" is a string array (which I don't know if possible), the code doesn't make sense at all because all the code will do is replace all multiple space characters into a single space characters. :?: