git - How to revert repository to commit

Question

I pushed a commit to the repo, and now the master repo is messed up and I want to revert master to commit a) which happened a while ago.

I can't modify the master repo directly so I have to create a pr to modify it. How can I revert master to the old commit a)?

I've tried

git checkout -b revertbranch
git reset HEAD --hard a
git add .
git commit -m "revert"
git push

However, when I try to open a pull request, I get a message on github that says no files are changed.

Can someone help?

Answer 1

git checkout branch_x
git reset --soft master
git commit -m "commit message"
git push -f "message"