I am being sued by Northern Leasing for a credit card machine bill from 2004. The contract was signed in Arizona and the court is New York County

You will  have to defend the lawsuit (it appears that you have a statute of limitations defense) unless you are absolutely certain that the New York Court does not have jurisdiction over you, i.e. that you have no contacts with New York (for example, did you send payments to this firm in New York, did you enter into the agreement in NY, did you send correspondence about the agreement or the bill into NY, do you own any real property in NY, etc.)  If you are absolutely certain that NY does not have jurisdiction over you, you do not have to do anything, because any judgment from a Court lacking jurisdiction is invalid.  However, if your adversary obtains a judgment from NY, they will try to enforce it in Arizona, and your only defense will be that the NY Court lacked jurisdiction.  If you lose on that issue, it will  not matter that you may have other defenses, such as limitations. From what you have written, I think it likely that the agreement you signed provides for jurisdiction in New York County, which would probably be a valid basis for jurisdiction.  Since the bill is so old, it is likely that the claim (barring other factors which you have not mentioned in your question) is barred by limitations, but you will have to either retain a NY attorney to handle the matter, or handle it yourself, which will probably require one or more appearances in NY.