If I know I can't make a game, and don't have a friend to transfer my tickets to, I mark the seats for re-sale immediately as that means if/when the exchange opens, my tickets are there straight away, maximising chances of a sale.
It also means you don't have to spend time trying to find out if...
To sell your season ticket for a specific game?
1. Go here (when logged in):
https://tickets.brightonandhovealbion.com/screenloader.aspx?type=include&page=usercontent/documents/html/resale.html
2. Click/Tap the "RESELL MY SEAT" button.
3. Scroll down to the game you wish to put up for sale...