As soon as you enter or update information in the medical information section, an option appears in the top-right corner of the app to re-evaluate the client. You can set the re-evaluation with one tap to 1, 3, 6 or 9 months, or tap "custom" to set a custom date.
When your client comes up for re-evaluation, you will get an in-app notification.
Here all all the main help categories in the Appilates user manual.