Thank you for your clarification.
You can file in NY for a name change, but court records are public records and the NY courts will not seal them unless you can prove that you would be in some actual physical danger if this information was known to the public. Once you get a name change, then the problem becomes Uruguay, which will require you to produce a birth certificate proving your nationality of parents to get citizenship unless you move there and apply for naturalization as a citizen and even then you have to provide proof of your name change because they will ask and they will find it. This is really an impossible mission legally to completely conceal your identity from the US end and you can talk to a Uruguay lawyer about on their end, but from what I found you are going to have to provide proof of birth (which would be something the court can change as part of the name change process) BUT you would also have to prove your Uruguay descent and that is where you would run into the disclosure problem.
You could instead of trying based on descent try for immigration and naturalization status like any foreigner without Uruguay descent, which is where you would have to talk to the attorney in Uruguay and you can find one at the same site used by attorneys, http://www.hg.org.
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