Hello, I'm going into third year materials eng and I was wondering if it was possible to restart engineering from first year all over. Would I have to reapply or something? Any response is appreciated.

Probably not, but you should contact an academic advisor since they would know the rules and your situation better than anyone here.

You can just switch to another program if your marks are good enough, or if not redo 1st year. Either way it's a very drastic thing to do. Advisers usually suggest getting your first degree then going from there, maybe trying a job or two and then getting another degree or masters.

You'd need a high average plus a detailed explanation/letter as to why. Talk to Gene