The approvals app allows you to set a manager for any user in Zendesk. Then in any approvals template, instead of specifying an individual approver, you can set the approver to "Manager" so that depending on who submits the request, the approval is dynamically set to whomever that user's manager is.
Here's a video on how the manager functionality works:
Using the 'manager' functionality means that if you have 50 approvers and you want to set the approver based on who the ticket requester is, instead of having to create 50 templates, it can now be setup in 1 template.
This also paves the way for companies who store all of their employee data in another system (for example Active Directory) as they will be able to map an AD field (Eg. Who an employee's manager is) to a Zendesk user field. This will allow seamless control of approvers from within the other system.