Reading Time: 20 seconds.

Step 1: Click People in the side menu

Step 2: Click Advanced

Step 3: Click Display Options...

Step 4: Under Show archived items toggle it to Show

This will show all archived users.

Step 5: Click OK

Step 6: Search for the user you want to restore.

Step 7: Click the Red Restore button on the right.

Step 8: In the dialog click Yes