If you enabled the "Four-Eye-Approval" process and need to approve/reject requests, these can be viewed within the [Four-Eye Approval Requets] screen. Note that these requests will only be visible to administrators. With the necessary rights, you will be able to "Approve" or "Reject" operation requests. On the other hand, an admin user without approval rights will be only able to view the requests.

To action these requests, click on 'Review changes':

Note that the administrator which submitted the change request will not be able to approve their requests