Yes. If you would like to give feedback on someone who is not in your list of suggestions, manually add coworkers via your Survey or your Org Chart.
Within your survey, scroll down to the end of your ratings list and select either Add coworker by name or Add coworker on org chart to browse your company org chart for additional people. You can also rate employees right from your Org Chart by selecting an org chart attached to an open survey. See the following video for details.