Help needed: How can I downgrade a Business subscription (TEAMS) to PRO?

Help needed: How can I downgrade a Business subscription (TEAMS) to PRO?

The FAQ Billing states that you can switch between the Pro and Business subscription types at any time. Unfortunately, it doesn't say how to do that.
(Screenshot 01)

A few days ago I did an "upgrade" from PRO to TEAMS (2 members). The result is not an upgrade of the previous "organization" of my PRO subscription - as I expected - but merely a new "organization" of type "Business" was added to my account (I think users should get informed about that before they upgrade, because they will have to manually move all their content to the new "organisation" to get the benefit of Business features).

Now I am wondering how I could downgrade to my original PRO subscription:

1) Opening my previous organization "Personal" via "Settings - My Subscription" I see the current subscription type is "Business". A link or button to downgrade to PRO is not to be found here.
(Screenshot 02)

2) So I switch to the new "Business" type organisation and open the "Organization Console" via "Settings - My Subscription - Manage". Here I see under "Billing information" that my current subscription type is a trial version with the name "Business Pro" for 30 members (so far I've nowhere read about that name).
It says here that after the trial period expires, the Business Pro subscription will be converted to the subscription I actually ordered (named "2 Members Package"). There is also a button to upgrade, but no button or link to downgrade to PRO (and to end the trial period).
(Screenshot 03)

3) This raises the following questions:

a) What subscription type does eventually apply here (so what do I have to pay for)?
Is it a Business subscription for 2 members plus a 30 day trial subscription for "Business Pro" for 30 members? Or is it a 30-day trial version of the Business subscription "TEAMS" that I ordered with the option to upgrade?

b) What does "Business Pro" mean when I actually ordered the "TEAMS" subscription?

c) And finally, how can I downgrade my Business subscription to a PRO subscription?