Originally Posted by Globaliser
I don't think you can do this online - certainly no obvious way suggests itself to me. AFAIK, it only allows you to select a seat for pre-allocation (whether for the first time or by way of changing). I think you probably have to call res for this one.
Having played around with function, Globaliser is spot on.
If you have any sort of OW/BA status you can get reservations to message seat control to open up a seat unless over 70% of the cabin has already been assigned hich is unlikely given 19E is still available.