In lib/post-types-and-taxonomies.php file you will get this line:
'rewrite' => array( 'slug' => _x( 'portfolio', 'portfolio slug' , 'genesis-portfolio-pro' ), 'with_front' => false ),
There have no filter for it. Still you can alter the portfolio slug without modify the plugin’s file. See the steps below:
Add the following php scripts in your functions.php file. Before editing the file you will keep a backup.
- Navigate to Dashboard -> Plugins -> Installed Plugins page
- De-activate the Genesis Portfolio Pro plugin
- Re-activate plugin now
- Now your slug is changed
If you need any help then you can feel free contact me.