You need to fill a form named: "Request for new PAN card or/and changes or correction in PAN data".
You can either download a correction form from the websites of UTI Technology Services Ltd (UTITSL), National Securities Depository Ltd (NSDL), or the Income Tax department of India or you can get a hard copy from any of the branches of UTITSL and NSDL. You can easily locate your nearest centre from the websites of UTITSL, NSDL or the I-T department.