If the marking is being too generous or too harsh, the fix is usually the mark scheme, not the marks. You can change the scheme right where you are moderating, check what it does to one student's answer, and then remark the class. A few clicks, rather than adjusting thirty submissions by hand.
This works on Long Answer questions in the New editor and Free Response questions in the Legacy editor.
Work out what is wrong first
Open the lesson's submissions from the classroom (Assignments, then the assignment, then the lesson) and click a question on the Blocks tab to see every student's answer to it. Sort by Lowest marks and read the Marking breakdown beside each answer: every criterion shows whether it was awarded and quotes the phrase that earned it. If the same criterion keeps going the wrong way across several students, the scheme is too loose or too tight.
Change the mark scheme
In the marking panel on the right, switch to the Mark scheme tab and click Edit mark scheme.
Change the wording, and the Marks allocated if you need to. Your draft stays put while you click through other students, so you can check it against a few answers before you commit.
Tip: write the scheme as text. A mark scheme that is only a picture (a photo or screenshot of a printed scheme) can't be split into criteria, so answers are marked without a breakdown and can come back with no marks at all. Type it in or paste it as text.
You need edit access to the lesson to save a new scheme.
Preview the result
Click Preview results. Mindjoy marks the answer you have open with the new scheme and shows it next to its Current marking, criterion by criterion, so you can see exactly which marks move before anything changes for real. Not right yet? Close it, tweak the scheme and preview again.
Save, or save and remark
The bottom of the preview tells you how many answers on this assignment would be regraded. Then choose:
Save and remark saves the scheme and regrades that question for this class straight away.
Save saves the scheme and leaves the existing marks alone. You can remark later from the lesson's Students tab (see below).
Remarking runs in the background, and the marking panel keeps count while it does: Remarking in progress, with how many answers have been remarked so far. Marks and feedback for that question can still change until it finishes, so let it finish before you return anything.
Answers you have marked or adjusted yourself are left as they are. Remarking only regrades the ones Mindjoy marked.
Where the Re-mark affected questions banner fits in
The mark scheme belongs to the question in the lesson, so saving it changes the lesson itself. Remarking from the review screen only covers the class you are looking at.
Any answers still marked against the old version of a question, whether you chose Save, edited the lesson from My Library, or the lesson is assigned to another class too, are flagged on that class's Students tab with the banner Some submissions were marked using an older version of the question. Click Re-mark affected questions there to catch them up. Remark free response questions walks through that route.
What counts as a change
Changing the marks allocated to a question.
Changing which option is correct, or the correct pairs or order.
Changing the mark scheme on a long answer.
Editing wording alone does not flag anything, so you can fix a typo without prompting a remark for the whole class.
What students see
New marks and feedback go straight onto the submission. If the lesson's feedback is set to show On return, students see them once you return the lesson (Moderate and return results). If it shows on submission or instantly, they see the new version the next time they open their work.