Tds not claimed while filing itr

vikram tiwari (nothing) (49 Points)

13 September 2019  
One of my friend file his income tax return for the F Y 2015-16 on 31/03/2017.
While filing itr he mistakenly forgot to claim his tds on itr.
After that department processed that return and no tds refund granted.
My friend file rectification request but department rejected the request.
Show now what is the procedure to claim the tds amount as refund?
Sir please guide.