Hii Arun!
The application process for ICAR has already finished on 31 March, 2020. And the correction window will open from 25 April, 2020 to 2 May, 2020. You can change your father's name and correct it then, as correclty in that detail is allowed. Remind you, not all details can be corrected once filled. Only Some , such as Candidate name, mother's name, father's name, DOB, gender, photograph uploaded etc.,can be corrected.
Hope this helps.
Good luck!