Theme Horse

Thank you for your recommendation to use a child theme. I’ve been trying to make one, but have a question:

How can you overwrite a parent theme function with a child function?

I want to overwrite require_once( ATTITUDE_STRUCTURE_DIR . '/header-extensions.php' ); in the parent function attitude_load_files with require_once ( get_stylesheet_directory() . '/library/structure/header-extensions.php' );

Regards,
Dennis