How do I enable another employee to act on my behalf to approve workflow items while I am out of office?

This feature is available on the Premier and Master editions
An approver in a workflow path can assign an alternate approver for a specified period using the Out of Office screen in their ESS profile. This allows the alternate approver to take action on workflow items on the manager's behalf.
Company level users can assign an alternative approver on this screen.
Navigate > Employee > Other > Out Of Office