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I am going to assume that this is in Georgia. Let me know if otherwise.
Assuming so, then the Petition for Legitimation & Custody/Visitation has to be filled out and filed with the Court. See HERE. The Court will then likely assign an ad litem/amicus for the child and may order a home review for the petitioner to confirm that they can take care of the child properly. Assuming this is passed okay, the Court will then decide whether or not to agree to the custody modification.
Note that if DEFACS is involved and has already taken the child out of the home, this complicates the matter. In this case, the parent does not have full authority to give all custody away - DEFACS has to agree. This is because if DEFACS as taken the child out of the home, they did so with the court's order. DEFACS has statutory right to stand in for custody of the child, and likely have done so in such a situation. Ergo, they have temporary (or permanent, depending on the situation) custody of the child and have to agree to any custody modification.
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