Rename slug of post_type

  function bmc_modify_builtin_post_args( $args, $post_type ) {
    
    if( $post_type == 'post') {
      $args['rewrite'] = array( 'slug' => 'blog', 'with_front' => true );
    }
    
    return $args;
  }
  
  add_filter( 'register_post_type_args', 'bmc_modify_builtin_post_args', 10, 2 );