With an active session in the same browser, it is not possible to log on to both sites as you have to log off or close the browser or delete the cookies or restart the browser (a mess, if you have active connections to other sites and a bunch of tabs are open).
Having the possibility to login with multiple accounts in the same browser will offer the users more comfort. E.g. In GSuite, I can easily change the used Google-Account.
Can you please consider this feature for a future release?