One method that i have done for myself and to people who are under me as students is to do a reversal of a baptism. So in many traditions in Latin America and other places in the world a body of water is used for removal of ones old self. Something that Abrahamic traditions use as well to initiate people into a specific religion. Cristians use the Baptism mimicking Saint John, The Jews use the Mikva or Purification ceremony and Muslims take the oath but perform acts of purrication with water before they pray.
So what i do is what my family and teachers have taught me. Bring a Special Bell, Rattle, or Drum to call the spirit you wish to work with. Bring some offerings such as Candles, Fruits, Liquors,Cigars, and ect. Always light your candle first before doing anything and specify who is it for. Bring things that the particular spirit or guide you are trying to contact really enjoys. Then remove the influence of the God or Spirit that was places above you and call on the God or Spirit you wish to come to you and represent you. Say you are immersing yourself to die and be reborn into the person you wish to become in the name or through the name of (who ever you want). After this Give thanks and you can make a pact, contract or prayer to the specific spirit. Give thanks and gratitude. Take some steps back wards at a reasonable distance and walk away.
Just my suggestion. Hope it helps.