How to change your world seed for your Minecraft server.
To change your world seed and start a new world, log into Multicraft, select and stop your server and follow these steps:
1. On the left hand side of your control panel click the "Files" dropdown box.
2. Click "Config Files"
3. Choose the first file named "Server Settings"
4. Scroll down to the Level Seed field.
5. Enter in your chosen seed.
6. Click "Save" at the bottom.
7. Return to the homepage of your panel, enter a new world name and start your server.