Apparently we will be sending around 300-400 back so i was told by the ticket office yesterday so either give them a ring or take a chance rovers will sell them on the day.
Or do what quite a few of us have done and buy a ticket for the home part of the ground and hope that you can sweet-talk the ticket office at the ground to let you swap, just explain how incompetent their opposite numbers at the Albion have been and see if that does the trick, assuming of course the tickets don't sell out and are returned.