Is someone coming back from leaving? Awesome! How can he get back to work immediately? By first activating the archived account again.
Archiving a user is only possible by a Full User. So make sure you have the correct rights before you start. Ensure that the right users have the right authority within project management.
How do you de-archive a user?
Go to the settings. You can get there by clicking on the wheel at the bottom left of the menu.
Then you switch the user overview from 'active' to 'archived' by clicking on 'active'.
There you see a circle to the left of the user photo with three balls in it.
In the screen that follows, you can make the choice to edit the user's data or you can de-archive the user. Click on de-archive to make the user active again.
Do you want to archive a user again? Then read this article.