[pfg_]

Yes, you modify the history uodating every commit after the changed one and then force push. Git has built in ommands to help. Anyone who has the repository cloned can tell if that happened because all the hashes will be different.

[Doxin]

As long as your git hasn't garbage collected the old commits you can still them back. you can just create a branch pointing to the previous HEAD and the whole history will still be there.