If you'd like to deregister your account by removing the email address and password for any reason, please follow the instructions here.
It's only possible to use an email on one Puzzle Quest 3 account, so if you decide you want to use your registered email on a different account, you can remove your email from the old account by deregistering the old account.
To deregister your account follow these instructions:
1. On any screen except during a battle, open the settings menu using the cog button in the top left of the screen
2. Select the Account button, which is the third diamond-shaped button on the left
3. Select DEREGISTER
3. A confirmation window will pop up, enter your password here to confirm and then press DEREGISTER
NOTE: Once you have deregistered an account you won't be able to recover the account using an email address or password, so if you want to go back to this account later, register it to a different email address.