Yes, you can switch your server to a different game.
First, create a backup from the Backups page. Then go to the Files page and delete all files and folders to prevent conflicts with the new game files.
After that, open the Settings page, find the Change Egg section, select the game you want to use, and click Apply.
Once you start your server again, it will run with the newly selected game.
If you need help with this, please submit a ticket.