# Undo a change

> Every turn that writes to a page takes a checkpoint first, so asking for the last change to be undone restores the words without moving the address.
>
> From the MightyBuilder documentation: https://docs.mightybuilder.ai/editing/undo

Changed your mind about what the AI just wrote? Ask for it back.

## How it works

The first time a turn writes to a page, it takes a **checkpoint** — a complete
copy of that page's draft as it was before. Ask the AI to undo, and it restores
that copy.

The checkpoint is taken per page, per turn. If one request rewrote three pages,
each of them has its own checkpoint from before that request.

A conversation keeps its checkpoints for as long as it is open, and they are
not tied to whichever page you happen to be looking at — so you can change the
homepage, walk to About, and then say "undo what you did on the homepage".

## What undo restores

**The words and the styling** — the page's content, its CSS and its JavaScript.

**Not the address.** Undo will never move a page, change its slug or change its
parent, and this is deliberate: an address that moves has redirects and links
attached to it, and quietly reversing that as a side effect of "undo the last
change" would break things pointing at your site.

If you want an address changed back, ask for that specifically.

## Undo is not the only way back

Undo covers the turn you just did. For anything older, **Overview → Releases**
has every release: what changed, when, and the ability to restore a page as it
was at any of them. That reaches back much further than a
conversation does.

The AI can read that history too — it can look up what a page used to say and
put a version back by name, without the whole document travelling through the
conversation and being retyped.

## If you have already published

Undo restores the *draft*. If the change you want to reverse is already live,
undo it and then press Publish, the same as any other change.