All I need to do is modify the commit message of some past commits in my branch locally, then push those modifications up to the server. I don't need to actually change any files in the past commits, and the past commits are not the most recent, they're from 2-3 commits ago.
Most answers I've seen deal with either modifying the files of past commits, or else just modifying the most recent commit message. Neither is quite what I'm looking for.
I'm hoping this is a quick and easy one for all you git experts :-)