Update value of $wp_session['session_name'] in woocommerce/wordpress

$wp_session = WP_Session::get_instance();
 is method to create your own  session in woocommerce/wordpress.
You can use $wp_session['session_name'] on any file in woocommerce/wordpress
after creating but if you want to change its value you need to first convert this object to array.

For creating array use
$temp = current((array)$wp_session['session_name']);

$temp return you the array / value assigned to $wp_session['session_name']...
Now use or edit $temp as your need and after use assign this array again to $wp_session['session_name']
using

unset ($wp_session['session_name']);
$wp_session['session_name']=$temp;
Example :
$wp_session = WP_Session::get_instance();
$temp = current((array)$wp_session['session_name']);
/***

Work with the array

***/
unset ($wp_session['session_name']);
$wp_session['session_name']=$temp;