Hello aspirant,

If you have registered for Jee Mains session 2 then its not an issue. You can register for session 2 as a fresh candidate. Even if you want to change anything from session 1, (like examination centre, caste or income certificate, etc.) then you must have to register as a fresh candidate. You can also register for session 2 through session 1 and withdraw your money but its not needed. Session 1 and session 2 registration both will act as a different candidate but your details are  same that's why you will not face any kind of issue regarding this. So don't worry and do focus on your preparations. Practice many of the previous year questions and give mock tests. These are also available on Career360. All the best.

Hope this helps you:)