To change the email address that is connected to your Open Diary account, start by clicking on the main menu and then on Profile.
Once you are at your Profile, click on the Settings dropdown, then click on Password and Email.
This will bring you to a screen where you will see your current email address, and you can change it to a new one. Note that you must also enter your password in the password box in order to change your email, this is to guarantee security of the account.
Once you have entered your new email address be sure to click the Save Changes button to confirm. You will receive an email notifying you that the email address on your account has been changed.
Remember that you will need to use the new email address to log into your account once it has been changed.