How to update/correct mother name in birth certificate online?

Hi. I am getting reissued my 5 year old sons passport and need to update my wife's name in that.

They told us to update my sons birth certiicate with my wifes new correct surname and then come. She's not indian. My son passport had her old name. My wife had it corrected in her passoport recently.

Can i update it online somehow or need to visit their office? If online then which site? If their office what documents they will ask for?

Please help. Thank you.