Nothing is deleted.
PlanbookEdu does not delete plans or remove accounts unless specifically asked to. A teacher removed from your group keeps their account and every plan they've written; they simply drop to the free version unless they subscribe individually.
What the teacher should do — before they go
Change the email address on their account to a personal one.
This is the one thing worth telling every leaver, and the one thing that becomes hard afterwards. Once the school address is switched off, password reset emails go somewhere they can't read, and getting back in means going through support.
They click Account, update the email, and sign in with the new address from then on — see Change the email address on your account.
Doing it a week before they leave takes a minute. Doing it a month after they leave is a support ticket.
Export anything they want as a file. Their plans stay in the account regardless, but a leaver may want their own copy — see Export an entire planbook.
What you should do
Email support to remove them from the group, or wait and handle it at renewal, when you're adjusting the roster anyway — see Renew your group subscription.
Removing someone frees their place against your teacher count.
Their turned-in plans
Weeks a teacher turned in were visible to you while they were in the group. Once they're removed, they're no longer one of your teachers, so don't rely on the dashboard as your record.
If you need to keep plans from a departing teacher — for continuity with whoever takes the class — ask them to export or share them before they go.
A teacher joining from another school
If they already have a PlanbookEdu account, don't have them start a new one. We can merge the existing account into your group so their plans come with them — see Add and remove teachers.