P/NP for a class in SIO already

Hi everyone,my gpa is nothing spectacular but could definitely be better, on my 3rd sem one class destroyed my gpa and I didn't use the P/NP fearing more difficult classes would come. So I was wondering if there's any way to change that grade to P/NP even thought is from my last sem. Turns out this sem was way better and since it's my last I have no need to use the P/NP any more