Thank you for the answer here on the forum.
I also started a trial.
Then I asked my manager, whether I also could become a registered user. No problem.
When he managed the subscriptions, I did get an invite, the invite has a number of steps, on how to proceed. After setting up my user on the website, I get some info on the website, and another email. Lots of steps are mentioned, also links to the documentation.
But somehow, within this extensive information, for which I am very greatful, this was still missing.
Add some info into the email on how to be able to change the signed in user.
But also, somewhere in the menu, provide a Sign Out link.
Even with your mention of the option, it took me some time to realise that the 'Sign Out' option, meant the little door icon. I simply totally overlooked it.