For KCET the last date to fill marks is on 18th september,2021. So now the portal is closed and what you will do is unknown as there are no instruction available from the organizers. I would recommend you to contact the helpdesk of KCET and get your doubts clear. They will surely guide you out.

The contact details as per the official website:

Karnataka Examinations Authority,
Sampige Road, 18th Cross,
Malleshwaram, Bangalore - 560012.
Phone No: 080 - 23460460
Website: http://kea.kar.nic.in
E Mail: keauthority-ka@nic.in (mailto:keauthority-ka@nic.in)

To know more about the KCET updates visit the link below:

https://news.careers360.com/kcet-2021-last-date-extended-for-marks-entry-submit-details-till-september-18

I hope this answer helps. All the very best for your future endeavors!