Sir, I have been registered for jee mains as fresh candidate but i want to cancel it and register as reappearing for April exam..

Dear M Vaishnavi,

From this year, National Testing Agency will hold JEE Main exam and as it is a national level exam it gives candidate a chance for correction in application form. As you have applied for April attempt, for which last date of filling form is 7 March, So correction process will only start after the last date of registration. Application form correction 2019 window will be opened from 11 March 2019. There will be an option for one time correction of personal particulars of candidates and it will be done only if the candidate have paid the fee and completed all the steps of online application form.

National Testing Agency

Block C-20 1A/8 ,Sector- 62
IITK Outreach Centre, Gautam Buddh Nagar
Noida-201309, Uttar Pradesh (India)
Telephone No. :  7042399521, 7042399525, 7042399526

Email : jeemain-nta.nic.in

You can contact them through mail or call, contact details given on official site as well.