Some users sign up through Facebook and then decide they want to have an email log in instead. To make this possible, simply go to 'Settings', select the 'Email' tab, add an email & create a password. After you have done these steps you can then unlink your Facebook credentials.
You can disconnect your Facebook account by going to your Profile page and clicking on the button 'Disconnect from Facebook' below your profile picture.
I want to add / change my profile picture
Customise and disable email notifications
I want to deactivate my account
I have two accounts and I want to merge them into one