I only have my first name on my birth certificate, but all other important documents like Aadhaar, PAN, and 10th marksheet show my full name with surname. The passport office is asking for document rectification. Some lawyers suggested filing a case to change it. What should I do?

You have two options: 1) Approach the passport office with an affidavit from a gazetted officer stating the discrepancy and the reason behind it. 2) If the passport office insists on rectification, consult a lawyer to file a case for name change in court. The court can then order necessary changes in your birth certificate.