How can I write in PHP a function that modifies an array?

Question

I would like to have a function that takes an array as input and changes some values of the array (in my case the array is $_SESSION but I think it does not really maters).

Answer 1

what you mean its call : Passing by Reference

its very simple like

function changearray(&$arr){
     $arr['x'] = 'y';
}

you can call this like :

changearray($_SESSION);