Impersona is not a builtin feature to Commerce. We have it in our backlog, but it is still a long way to get there
Whilst not yet a built-in feature, the Quicksilver B2B implementation on Github has this feature. https://github.com/episerver/QuicksilverB2B
Once installed, log in as admin and then go to the profile page. You'll see a link to organisations - click on the top-level one and then look at that organisation's users. Next to each user you can click an 'eye' icon that will let you impersonate that user.
Once impersonating, you can act on that user's behalf, and when finished click on the 'return to admin' link at the top of the page.
I hope that helps
Thanks for the information Quan!
I will install the QucikSilverB2B and check it out. Thanks so much for the tips Marcus.
our client is asking for a feature, in which their employees (admins) have a list of Organizations, which they can switch to (login as).
We have some ideas with setting 1:N relations on CustomerContact, getting the Organizations who the contact has acccess to, but we are unaware about difficulties or problems which may come with this solution.