User product price will not changes after changing customer group on the same session

I have two customer groups like

CG1 and CG2 and for product A

CG1’s price is 10 $

CG2’s price is 20 $.

my user is currently on customer group 1 (CG1) and i switched him to customer group 2 (CG2). But when am switching him from group 1, his current session was on, but the product price didn’t change to 20$ immediately. Only after re-login he was able to see the updated price.

where is magento storing this session, how can we forcibly update even if the session is on ? is there any kind of caching we need to clear.

How to resolve this