Why is my procedure not changing the array - arrays

Question

I have a procedure to shift the position of the array values
The string at position 1 is supposed to take the value of the string at position 2, and the string at position 2 is supposed to take the value of the string at position 1(and so forth)
eg.
The array at the start:
Pos Value
1 A
2 B
3 C
The array at the end (what it's supposed to become):
Pos Value
1 B
2 C
3 A
This is the code:
unit Unit2;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, ComCtrls;
type
arrRotor = array [1 .. 10] of string;
TForm2 = class(TForm)
Button1: TButton;
RichEdit1: TRichEdit;
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
procedure ArrayShiftRowUp(arrArrayShift: arrRotor );
end;
var
Form2: TForm2;
j, i : integer;
temps:string;
arrTest: arrRotor;
implementation
{$R *.dfm}
procedure TForm2.ArrayShiftRowUp(arrArrayShift: arrRotor );
begin
for i := 1 to Length(arrArrayShift)-1 do
begin
tempS := arrArrayShift[i];
arrArrayShift[i] := arrArrayShift[i + 1];
arrArrayShift[i + 1] := tempS;
RichEdit1.Lines.Add(arrArrayShift[i]);
end;
RichEdit1.Lines.Add(arrArrayShift[10]);
end;
procedure TForm2.Button1Click(Sender: TObject);
begin
for i := 1 to 10 do
begin
arrTest[i]:=Chr(64+i);
end;
for i := 1 to 10 do
begin
RichEdit1.Lines.Add(arrTest[i]);
end;
ArrayShiftRowUp(arrTest);
for i := 1 to 10 do
begin
RichEdit1.Lines.Add(arrTest[i]);
end;
end;
end.
But for some reason, the actual array is not changing. The array parameter is changing (as evident of the display in the rich edit) but for some reason, arrTest is not changing.
What is the issue?