Players can be transfered to other users with Teach Your Monster accounts via your player dashboard - https://www.teachyourmonster.org/account/players
Select 'transfer players' from your global action menu at the top of your dashboard
Select which players you want to transfer (you can select all, a group or an individual)
Enter the email address of the account you want to transfer them to. The user must have a Teach Your Monster account.
Confirm the transfer
Your players will be transfered. In some cases players can't be transfered, this is usually when the other user already has a player with this name.
You can only transfer players - their group names will not be transfered.
To transfer your whole account, the best option is to edit your email to the email address of the person taking over your account and letting them know the password. You can do this here.