How do I change the rating type in review settings?

Enabling Period Grading

Go to Settings, then Review, then General, then Settings.
Click Enable Review Period Grading to turn on period grading.

Changing Review Period Rating Wording

Go to Settings, then Review, then General, then Review Period.
Click the pencil icon to edit the wording and colour of a rating.
Change the order of the gradings by dragging and reordering the grading types.