You need to commence a name change proceeding. The link to the instructions/forms is as follows: http://www.courts.state.ny.us/forms/namechange.shtml. You should note that the biological father will need to be served with a court summons. Nevertheless, I advise you to consult further with a Westchester Co. Family law attorney.
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is it an adoption or just a name change?
If this answer is helpful, then please mark the helpful button. If this is the best answer, then please indicate it. Thanks. For further information you should see an attorney and discuss the matter completely. If you are in the New York City area, then you can reach me during normal business hours at 718 329 9500 or www.mynewyorkcitylawyer.com.