Currently, it is impossible to reset in-game progress on a game account.
You can start a new game by logging out of your current profile, and creating a new one.
If you'd like to use the same email address with a new account, please follow the steps below:
1. Open your Profile page on Plarium Play
2. Switch to the Settings tab
3. Go to the Account Settings
4. Change the current email address to a fake one
Now, after you log out of the current account, you will be able to create a new one using the initial email address. A new game profile will be assigned to you.