no ur seat doesnt have 2 b surrended to take part in spots.if u get some othr branch in spot,only then ur current seat is lost.
if u dont get othr branch in spot.u can continue wth ur current seat.if u get any othr branch in spots thn ur current seat will b put up 4 othrs in d same or any later spot admissions
no particular rule 2 participate in spot.
also remenber u can always change branch after semestr 2(1st year)