Commits

List all in a branch, not in another

git log --no-merges <in_branch> ^<not_in_branch>

Note: on Windows command prompt (not Powershell) ^ is an escape key, so it needs to be escaped with another ^

This changes the SHA-1 of the commit and all its children, so it's something to do locally or on a merge/pull request.

git rebase --interactive <hash>~: the tilde means reapply all other commits, this will set that commit as current for editing
in the default editor, modify pick to edit in the line mentioning <hash>
make required changes
git commit --all --amend --no-edit to amend the changed commit
git rebase --continue to complete