SSC does not offer re-evaluation or rechecking of answer sheets or OMR sheets.
The only remedy is the provisional answer key challenge window — raise objections with proof before it closes.
Once the final answer key is published, the result prepared on it is final and binding.
UPSC and RRB follow the same policy: no re-evaluation after the final result.
A few state boards and universities do allow rechecking with a small fee, as per their own rules.
Always read the result notice — it states clearly whether any rechecking route exists.