To remove formative assessment data you would go to My Subjects, select the required assessment class and click the Formative Markbook.
Select the checkpoint you require, the statement component and 'Choose'.
In the top left hand corner of the screen click onto the red arrow and you will be in undo mode, now click onto any marks that are incorrect and each click will go back one mark. Once complete click onto the red arrow and you can continue entering marks as expected.
If you are not able to change the marks, hover your mouse over the mark to see which Checkpoint the data was entered at. In the example below, the data was entered at Checkpoint 6 instead of Checkpoint 5, so you would need to go to SUM2 in order to change that mark.
Please be advised that you can only remove marks at the checkpoint they were entered. If you are unsure which checkpoint the marks were entered in, if you hover your mouse over the mark it will display the checkpoint and date of entry.
Please note: Formative data cannot be removed in bulk.