Hi gjkris,
Am slightly confused whether you are in UK on a "student visa" or "work permit" visa
If you are a full-time full fee paying international student in UK on a "student visa" and that "student visa" is due to expire before you can re-sit your exams, ask your college / university administration office to issue a letter to you stating that you have re-appear in the examination. On basis of this letteryou can ask your college / university office to write a letter that you need to sit your exams again. On basis of this letter you can apply for further leave to remain (FLR) using form FLR(O) to extend your visa validity. You will need all the supporting document as specified in the guidance notes / form - finances and accommodation being the key.
If you are in UK on basis of Work Permit visa or have WP approval from HO, I don't think you need worry. You can switch from student to WP visa in-country.
Hope this helps.
regards
