Access variable from one form to another

[question]

I have followed your method, i have clarify my situtaion again, please need some more hints

Procedure TForm1.Person1(ID:Integer);
begin
//The value of this ID come from database with sql query
for example, after query here is the value of ID = 120;
end;


Procedure TForm2.Button1Click(Sender: TObject);
begin
Form1.Person1(Form1.MyPersonID)
//when i call here Form1.MyPersonID, then it passes the value '0' to TForm1.Person1(ID:Integer)
// but , i want to call the value 120
end;