An account Manager can switch session to handle your account on your behalf.
To access the Permissions:
open the avatar menu by clicking on your picture in the top right corner of the site
click "Account settings"
in the left sidebar click "Permissions"
To grand the manager access to another user:
click the green button "+ New"
insert the email of a registered user in the according text box
select "Manager" in the permission dropdown
To remove the manager access to another user:
click the red button "Remove" next to the according