SMP code is a change code for Password, Mobile Phone, Email. It can be used to change your password, mobile phone number, email address, delete your account. It is valid once, if you use it again you will need to download a new code to change something. Enter your character name (username, account name) and click the Get SMP code button. An SMP code will be emailed to you. Then go to Main Page - Account Settings and select what you want to do.