hi,
see once you fill the form and submitted it you can not change your category and it is not permissible in many of the entrance exam. since you have applied from obc category, your score and seat would allotted as per this category only. it may possible that an obc students get higher score then general category, but if you have applied for obc category, your have to accept seat which allotted for obc category only.
hope you understand.
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