How long does a faction change take to go through?

[Perl-anetheron (Perl)]

Have a look at the post linked below. They seem to have a solution:

Faction Change missing portals

SOLUTION (confirmed working for horde-to-alliance-xfer in 8.3) For Boralus: Go to Stormwind, pick up Tides of War. Follow Jaina to Boralus, skip all the scenarios if you want. Follow the intro quests in Boralus until you complete the quest “Sanctum of the Sages”. Wait for the Stormwind portal to appear - go through it, load into the Stormwind portal room, turn around and take the Boralus portal back (it should be working now.) Now you’ll probably discover that you can’t get into the Chamber of…