Content Sync provides you a couple of different update behaviors you can use. See Pull updates here for details: Flow Pull Options. By default, content that was pulled can only be changed on the source site to keep the content editing workflow simple; in this case, editors see the following message when trying to edit content that was pulled in from another site:

The message includes a deep link back to the source site to change the content there.

By default, content that was pulled into the site is automatically updated whenever an update is pushed from the source site. Another option is to allow editors to override content locally after it has been pulled. When configured, content that was pulled will not show the edit form until the editor explicitly enables local changes:

Once enabled, editors can make local changes:

Content receives updates automatically from the source site until it is overridden. Overridden content is no longer updated to keep local changes persistent. Editors can reset the content and remove local changes to reconnect the content to the source site and receive future updates again:

Once the removal is submitted, Content Sync automatically resets the content to the latest version from the source site:

With our views integration you can easily expose a filter to allow editors to find content that was overridden locally: