Edit or hide portfolio slug

Hi, I’m about to start a new project and would love to use the highend theme. The only issue is that it will be essential to either hide or change the ‘Portfolio’ slug. Rather than http://www.website.com/portfolio/example, I would require http://www.website.com/venues/example.

I know this used to be a fairly simple change to the ‘theme-custom-post-types.php’ file but do you have any advice on how I can achieve this with the latest version of the theme? At least some pointers in the right direction?

Many thanks