From your console, you can deactivate and reactivate a user at any time.
1 - Access your team settings
From your profile (top right), access the "Manage my team" menu
2 - Click on the "Users" tab
Then click on "deactivated"
3 - Modify the user
You'll find all your console users.
Click on the 3 dots at the end of the user's line, then on "Reactivate".
The user has now been reactivated.