Hello, thank you for contacting Ucraft Support Service I’m Vartan and I’ll be happy to assist you today!
There is an Undo button at the bottom left corner. Have you tried to click on it?
However, note that the Undo button will not work after you refresh your page.
In addition, we do have a 'Publish' button, which gives an option to publish/unpublish your recent changes, while in case the functionality is disabled or the subscription is the Free Website plan, all the changes made on your page are being automatically saved and your site goes live without publishing on.
If you want to have several versions of your website and be in control of what is published and what is not, you can enable 'Site Versioning' from the Site Settings App. You'll then notice the 'Publish' button appear on your left tool panel. Now, when you make changes, the button will become clickable, so you can publish the edits manually. Also, your Ucraft Subdomain always carries the latest version of your website, you can publish changes on your custom domain name.
Here's an article for more insight!