Originally Posted by thijsseh

Have you tried via 'manage my booking' (I assume you have an active, valid booking in the system)?
Go to 'passenger preferences' just below the itinerary there ia an area called "Mr (or Mrs) MareLuce's information". When you click the red 'update' button to the right, you can change "Emergency Contact", "Contact details" and "Passport detail"s. Works in Safari for me.