Question : After I accepted my offer, can I remove it from my preferences to add another course in its place? What effects would that have if I did do that?
Why do you want to remove the offer you accepted? If there's another course you want to get into, just move it above the course you've accepted and you'll get considered for second round.
I want to remove the offer I accepted because ... well I got into it LOL there's no use for it to be there anymore ..
And I just want to shove another course into my preferences to see if I would get offered a place in later rounds because the course i got offered wasn't really what I wanted, yeah.