Prophicies to Factions - how?

I'm almost done Prophicies, and I just purchased Factions. How do I transfer my char from one to the other? And can I go back again?

While I'm here, I guess I should ask the same question about NightFall, as I intend to purchase that once I'm factions.

You take the quest called Mhenlo's Request from Firstwatch Sergio (Skill Trainer) in Lion's Arch.

http://gw.gamewikis.org/wiki/Mhenlo%27s_Request

Krat

And don't forget to add a new Factions keys into your GW account, do not make a new account if you wish to conect the two game together.

And you can travel back and forth as often as you like, just by hopping on the ship to and from Lion's Arch

imo they should answer this question once and sticky it.