Approve Recommendation’ action is available in the ‘My Action Itemsscreen (Performance -> My Action Items).

Click ‘Approve Recommendation’ link; it will take you to the following page;

This page contains the recommendations and feedback provided with options to Approve/Reject.

By Approving a recommendation the workflow proceeds with the next activity and Rejecting will reopen 'Provide Recommendation' stage and then the managers can make the necessary changes. During rejection, rejection comments can be entered and the same is visible for the manager in the system. Synergita can be configured to trigger an automatic email notification to draw the attention of the manager. 

PS: Synergita implementation for your Organization may vary from how the features are described here. The screen shots given here may also be different from what you see in your system. Please talk to the concerned person in the Organization for any specific queries.