Roblox retains copies of all uploaded places. This means that any time you make any changes to a place and publish them to Roblox, a copy without these changes is saved as a past version. You can find and revert to one of these older versions at any time by doing the following.

Change to an Earlier Version:

1. Click on Create, located at the top of the screen
2. From here, find the place you wish to configure
3. Click the gear-icon, located to right of the place name, and click Configure Start Place in the menu that displays.
   
4. Click Version History. Here you will see a list of your past versions ordered by date
5. Chose the version you wish to make current
6. Click Revert to this version to make it the current place

Additional Help

Creator Documentation