Just to clarify some false statements above: you do not have seats assigned at this time. Assuming that you do not hold Oneworld Sapphire or Emerald status, and are not traveling on a full-fare ticket, you will not have a seats assigned until you begin the checkin process, at which point you will be able to change your assigned seats to any available ones in the cabin. Whatever seats are shown as taken on Expertflyer have already been assigned to status-holders and full-fare flyers already.