Just to make sure folks understood teh question, I'm not thinking about multiple HQs, only moving the location of our current HQ.
OUr situation is that our 7x7 was transformed into a conf center (not a cathedral, wee started jsut before they were released). we have a better location in mind for a HQ, so we were hoping that we coudl build a cathedral (we don't actually have one yet) and than transfer HQship to it. I wasnt sure if teh current rules stipped you from building HQ facilities, or if they prevented you from having those facilities officially serve as HQs (for starting locations).
The Conference Centre is the HQ facility for Service class of factions. The only situation in which a facility could be transformed into a HQ would be if the faction didn't already have one. If you get a HQ from the 'new HQ every 20 active members' rule it'll be a single use datacard that you can build whereever you like. Once it's built it'll appear on the starting facilities list automatically.