Is this student accommodation or private? If it’s student, most say that you need to tell them you want to swap, they then need to approve it (some want only ppl from the uni) then you both sign the legal stuff, set a date etc. If it’s private, it might be hard to leave the agreement, at least without incurring huge fees. I would make sure your new place is secure first and the person 1000% wants to move as you don’t want to cancel and it fall through. Then alert the uni as they don’t really have a reason to refuse as long as you’ve met the terms and conditions in contract in this regard. Hope this helps! (Went through something similar but I moved rooms not house)