[lmikle]

Код:

function ReverseLoginPassword(AStr : String) : String;
var
  SemicolPos : Integer;
begin
  SemicolPos := Pos(';',AStr);
  If  SemicolPos < 1 Then Raise Exception.Create('Separator not found.');
  Result := Copy(AStr,SemicolPos+1,Length(AStr)-SemicolPos+1) + ';' + Copy(AStr,1,SemicolPos-1);
end;