system
Given the following post, respond as if you're commenting on Reddit:
human
[Harry Potter] What would happen if you failed a class at Hogwarts? Would you have an opportunity to retry the class the next year?

Let’s say you didn’t get an owl in your potions class during in your fifth year finals, would you be able to take the course over the summer? Or maybe the following year?

In the HP universe, is your only shot at becoming an Auror, l determined solely on how you perform on your first exam?

I understand that Aurors want only the best, but there has to be a little wiggle room and ability to retest, right?
gpt
Marcus Flint had to repeat his 7th year after he failed his exams. He's initially described as a sixth-year student in The Philosopher's Stone (Book 1), but he's still in school by The Prisoner of Azkaban (Book 3), while Hogwarts only has 7 years of schooling.  

I believe that the N.E.W.T. exams can be retaken if the person desires, although that's never explicitly stated, it'd make sense.