You can customize the options for response codes in two separate locations. The first is (from your dashboard) under Admin > Classifications. Then find the table called 'Reviewer Response'. If you open that table you can add/edit/remove values that each represent a different option. When you are done, click save and close.

You will then need to add the responses to the review stage that you are using. This is under Admin > Reviews > Review Stage Setup. Double-click the review stage that you want to customize the response codes from. Under the feedback section, you will see a Check box next to 'Response Codes' If this is checked, then the checked values in the box below it will be included as options on any review that is associated with that review stage.