How to modify a specified commit?

Question

I usually submit a list of commits for review. If I have the following commits:

1. HEAD
2. Commit3
3. Commit2
4. Commit1

...I know that I can modify head commit with git commit --amend. But how can I modify Commit1, given that it is not the HEAD commit?

Answer 1

For me it was for removing some credentials from a repo. I tried rebasing and ran into a ton of seemingly unrelated conflicts along the way when trying to rebase --continue. Don't bother attempting to rebase yourself, use the tool called BFG (brew install bfg) on mac.