If you probably intend changing your subject combinations then you can do it once again as JAMB re-opens the portal and it closes on Friday, 12th of May 2017 at 10 am. Read the instructions as directed by Jamb "The window for correction UTME subjects combination is now available and closes by 10am on Friday May 12, 2017.
Please note that if your Examination date is Saturday May 13, 2017 and you correct your UTME subjects, you won't be able to write your exam on that date again. A new Examination date and time shall be communicated to you at a later time. The change in date of Examination does not affect other Examination dates. Visit the nearest CBT Centre for this correction. The Change of UTME Subjects Combination is FREE!!!" With that above instruction, all those who still want to make some changes to their selected subjects can still do it before 10 AM tomorrow at any CBT Center!! Goodluck!!!
http://www.macdanielsblog.com/2017/05/the-correction-of-jamb-utme-subjects.html