“What is done cannot be undone, but one can prevent it happening again.”
“What's done cannot be undone.”
“What is done can never be undone.”
“What you have done to this point cannot be undone. What you do next... It is still unwritten.”
“Nothing has ever happened in the past that can prevent you from being present now; and if the past cannot prevent you from being present now, what power does it have?”
“Evil can be undone, but it cannot "develop" into good.”