Hello Robb,
Thank you for reaching out. Apologies for the inconvenience. Unfortunately, it is not currently possible to directly modify an existing Saved Item, and changes do not automatically update across instances where it has been placed.
However, you can follow a workaround: insert the Saved Item into a page, make the necessary edits, then save it again as a new Saved Item and remove the previous one. This will allow you to achieve the same result with the updated content.
If you have further questions or need assistance, feel free to let us know.