Unarchiving restores an educator account, with everything they made still attached to it.
Getting there
Click your organisation name at the bottom of the sidebar and choose Organization. You need to be an organisation admin to see it.
Open the Educators tab.
Finding the archived account
1. Turn on Show archived. Archived educators carry an Archived tag.
Unarchiving
2. Click the three dots at the end of their row and choose Unarchive.
3. The account returns to the list without the Archived tag, and the educator can sign in again.