Caste is attached to your birth. You can not change it. According to indian smritis it is in your blood.
Even by marraige of higher caste boy you cannot change your caste. There is no law to change caste.
Courts can declare existing status. It cannot creat/confer new status or caste.
One can change religion but not caste.
But don't worry. Classification of a prticular caste as schedule caste is done by the government for the purpose of granting benefits.
Caste identity is required only if you seek any benefit under the schemes.
Otherwise, you need not identify with a caste. You can say that you are against caste system and that You don't belong to any caste as such.
LET US CREATE A CASTELESS SOCIETY