is it possible to ask to write exams earlier than the scheduled date? if so how do i go about doing this? and if not would i be able to defer the exam?

something, that is out of my control, overlaps with one (kinda 2 actually) of my exams and i was wondering what i can do about it

please help!!

If it is due to an exam conflict (the rules for what constitutes a conflict are clearly described on the registrar's website) then you can get it moved.
If not, you'll have to have an acceptable reason to defer it until reading week - documentation is required. Though, I have heard that they tend to give everyone one "freebie" (i.e. deferral without a good reason), but I wouldn't want to bank on that.