I created a commit that includes changes to several files, which are ok, except for one. This file was already in Github and my PC but I wasn't supposed to change it in GitHub (only in my PC if I needed to do so). So when I was creating a pull request, in the previous step where it shows you the changes, it shows the changes.
I tried to fix this with git revert -n [hash of the commit] but it reverts everything and I just need this file to not show up as changed in the GitHub pull request.