This is a very easy way to transfer ownership of your guild to an alt (on the same account) without entrusting it to a middle-man.
This is also the only working method I know of. Usually when you use the /afk \n macro, your alt will remain online but cannot be promoted to GM because it will appear guildless.
Method:
1. Log onto your alt char.
2. Create the disconnect macro (/afk \n) and place it on your action bar.
3. Go to any instance portal - Ragefire Chasm and Stockades are two easy ones.
4. Run into the portal and press your macro at the same time.
5. Log onto your GM char.
If all went well your alt char should still be online and eligible for promotion.
Note: If you try doing this without Steps 3 and 4 it will not work.
Forgive me if this is a repost. I've never heard of the method before I discovered it, and I can't find it anywhere else.
~ Baz