This is the place where you can give another person (in your organization) a responsibility for your mailboxes, calendars or task lists. Delegated person will have access to selected folders (write or read-only) and will have possibility to act in your behalf, e.g. reply to email, create events/tasks, handle invitations.
To add a new user delegation use “Add delegate” button, type user name in the form on the right (wait for auto-completion and select the user from the list) and select folders to share.
You can modify access rights at any time, remember to use Save button.
When removing delegation you’ll be asked if you want to remove also access rights to folders that previously were given access to. So, you can remove delegation but keep folder permissions for this person.
You can always change folder permissions in Settings > Folders.
The delegation feature to fully work requires from the delegated user to re-login. In this process new identities will be created on delegated user account. They will be removed when the delegator removes the delegation (depending on server configuration).