If you created an account with MyAlbum using an email address you can change the password and e-mail address on your profile. Select your avatar on the top right and select Profile.
In the login screen 'Login with MyAlbum' click on the link "I forgot my password'. Enter the e-mail adress you used to create an account with MyAlbum. You will receive an email allowing you to reset your password and restore access to your account.