Zequester

Hello everyone, I'm relatively new to Prestashop, so please forgive me it this is something easy to fix. When I don't have products in stock, a customer can order as much products as he/she wants, but when I have a certain amount of product in stock, a customer can order up to that number and not more. How can I make it possible for customers to order more products than I have in stock? All I would like to change is the notification from "In stock" to "Available to order". I hope that you understood my question. This is the link to my website: http://stolicefotelje.rs Thank you in advance, Best regards, Dragan