well, i would think it would be like any other revert - you say the shahadah.
i don't see why it would be different.
i'm not a muslim - maybe a muslim member will see this and correct me if i'm wrong.
Go to a mosque. Talk with Imaam (or ask a brother/sister that you want to revert). The Imaam will tell you all you need to know. You'll have to say shahadah and then you're a muslim.
if you come back then come back without doubts, dont be one to fulfil the prophecy "believer at night and disbeliever at morning". SubhanAllaah its shocking how many treat islaam like pages which can be turned back and forth.