[Theme: Adapt] How to change "portfolio" in URL?

Hello,

I have installed on my website a theme with a portfolio section, in addition to the classical page and post.
So I set up some pages, a blog and my portfolio. The general page for my portfolio is: http://devargas.com.es/works/ but, when entering a single project http://devargas.com.es/portfolio/reforma-piso-eixample-diputacion/ it show “portfolio” in the url instead of “works”.
I’ve been looking for how to change it for quite a while, but can find the way… Any help would be most welcome!!
Thanks,

Anne-Sophie