change of category from obc to sc

Dear sir/madam, i am a civil service aspirant and appeared in the exam with gadariya community which belongs to obc, i wrote two times mains of civil service by this certificate.. now i came to know that originally i belongs to dhangar community which is listed as sc community in central government list.. dhangr is subcaste of gadariya.. now i want to take my attempt with dhangar certificate.. so i want to know that may i face anykind of problem.. although very few people have dhangar certificate as it is very difficult to get.. kindly guide me in this direction.. thank you