Live ORACLE

 DECLARE
n  NUMBER := 10;
PROCEDURE Do_something
   (n1  IN NUMBER,
    n2  IN OUT NUMBER,
    n3  IN OUT NOCOPY NUMBER)
IS
BEGIN
n2 := 20;

dbms_output.Put_line(n1); -- prints 10

n3 := 30;

dbms_output.Put_line(n1); -- prints 30

END;
BEGIN
Do_something(n,n,n);

dbms_output.Put_line(n); -- prints 20

END;
/  

10
30
20

PL/SQL procedure successfully completed.

Aliasing Passing Same Parameter Multiple Times