Move

function MoveTPA(var arr: TPointArray; oldIndex, newIndex: Integer): Boolean;
var
  h, i: Integer;
  t: TPoint;
begin
  h := High(arr);
  if ((h > 0) and InRange(oldIndex, 0, h)) then
  begin
    if (newIndex < 0) then
      newIndex := 0
    else
      if (newIndex > h) then
        newIndex := h;
    Result := (oldIndex <> newIndex);
    if Result then
    begin
      t := arr[oldIndex];
      if (oldIndex > newIndex) then
        for i := oldIndex downto (newIndex + 1) do
          arr[i] := arr[(i - 1)]
      else
        for i := oldIndex to (newIndex - 1) do
          arr[i] := arr[(i + 1)];
      arr[newIndex] := t;
    end;
  end else
    Result := False;
end;

var
  TPA: TPointArray;

begin
  TPA := [Point(0, 1), Point(2, 3), Point(4, 5), Point(6, 7), Point(8, 9)];
  WriteLn('BEFORE: ' + ToStr(TPA));
  MoveTPA(TPA, 1, 4);
  WriteLn('AFTER: ' + ToStr(TPA));
end.