Dropping students from Summer School follows the same process as dropping a student from any type of school
Step 1: Navigate to the student's Demographics page
Step 2: Click Change
Step 3: Change student's Status to Inactive
If the student attended even one day of the Summer School Session you should set them to Inactive
If the student didn't attend the Summer School at all and will not attend at any time during the session, the student may be No Showed and the record may be deleted altogether. This would be a district decision.