How do you change your faction's capital?

As Prussia, I can't find out how to change my faction's capital from Brandenburgh to Boston. Or to any other city for that matter.

:help:

I'm pretty sure that you cannot move your factions capital.

Well, its not like there is a capital distance penalty any more.

It's for migrational purposes.

I think Divine Wind is right: I seem to recall reading somewhere that you cannot move your capital anymore.