Hi aspirant,

while registering a form it is generally mentioned that one need to be extra careful while filling a form, because those are irreversible fields. So it is impossible to change. However you can give try to contact their helpline details. From website you can get helpline number or mail id. Just try to call them ot mail them and convey your mistake. Upto some extent they can help or can guide you.

hope this is helpful to clear your dilemma.