I was in touch with the concierge to arrange spa and restaurant bookings so just asked them to put me in touch with the appropriate person. The front office manager then reached out and we worked out the upgrade from there. I would take a look at what inventory is still available for sale over your dates closer to your stay and decide whether you want to pay for an upgrade. For my dates the inventory gradually dwindled down and completely disappeared about a week prior to check in. Good luck!