I booked a China Eastern international business class ticket on their UK website. Completed the payment and got an Air Ticket Issue Confirmation e-mail with the 13-digit ticket number and 16-digit order number on it. No 6-digit booking code though. The e-mail says to click the link to go to Manage Booking for seat selection. Did that and entered my ticket number and name to see my reseveration, but there is no option for seat selection.

How can I select seats? Thanks