There is no option to change the e-mail associated with your account, however you may 'transfer' characters by merging two accounts. Create account on e-mail you want, go to dragoneternity . com , log in with your new credentials, press 'Settings' button in authorization window and afterwards press the button 'Add Account' once you fill out needed details characters from that account will be added to your new e-mail/account.

(Guards do not work weekends, so I copied and pasted this from one of Ihit's comments on a similar subject.)