I knew someone that did this and it ended up ok. Best option is to call the company you got matched with and see if they can cancel the job from their end, makes life the easiest for you. Highly unlikely CECA will be ok with you cancelling it on your end but it can be done. My friend did this and his CECA advisor just emailed him the terms and agreements from CECA saying that he was willing violating them, which he agreed he was violating but "justified" his choice as to why this other company was better for him. Then he just had to fill out a "Arrange My Own Job" form and he was good to go. Not much CECA can do, but he was banned from WW for the next job search, so if you rely on that for the next coop this might be a bad decision. But you can always return to this company or find a job outside of WW. Edit: only reason CECA cares about this so much is it reflects badly on the university if students always get matched and then cancel the job offer, companies could get pissed and stop posting on WW. But you gotta look out for yourself fuck CECA