We needed to find a new customer’s reseller account for Office 365. It is easy…

1. Log into their Office 365 account.
   If you are locked out of the admin account start the process to correct as soon as you can.
2. Our accounts show an “Admin” button on the dashboard/splash screen, click the “Admin” button.
3. On the left-side menu expand “Settings” by clicking on “Settings” and select “Partner relationships“

The following article got me headed on the right path.

https://support.office.com/en-us/article/find-your-office-365-partner-or-reseller-b6c18a9b-2aed-4c84-9d75-af709160258c

Let us know if this helped you…