Do NOT contact the employer directly. It could jeopardize the process.
New York is somewhat unusual in that a wage (income) garnishment is a two-step process. The following is excerpted from the Erie County (NY) Sheriff Department:
"Brief Explanation & Fees for Common Civil Processes and Instruments
1. Income execution, CPLR 5231.
This instrument, commonly known as a wage garnishment, is used to satisfy a money judgment from the debtor's earnings. There are two stages. In the first, the income execution is served by the sheriff on the judgment debtor who must begin making voluntary installment payments to the sheriff. The income execution must be filed with the sheriff where the debtor resides. Therefore, the creditor must have a current correct home address for the judgment debtor. If the debtor fails to make the required voluntary payments, the second stage begins. The income execution will now be served by the sheriff on the debtor's employer who will deduct a percentage from the debtor's earnings and remit it to the sheriff. The income execution must be filed with the sheriff in whose county the employer is located. So, for example, if the judgment debtor lived in Erie County and worked in Niagara County, the judgment creditor would first have to file with the Erie County Sheriff and if the debtor defaulted, the Erie County Sheriff will return the papers to the creditor who must now file them with the Niagara County Sheriff. The fees listed here are for the Erie County Sheriff charges; you must call other sheriffs for their rates. All fees are paid at the time the papers are filed. If the debtor lives & works in Erie County, both 1st and 2nd stage fees are paid in advance. The income execution can be issued (or signed), only by a lawyer, court clerk or county clerk.
*Make sure the original is indorsed by the residence county sheriff and the judgment balance/interest date are properly adjusted.
Whenever more than one Sheriff (or county) is expected to be involved and the judgment is from a City, Town or Village Court, the creditor must first obtain from the original court a transcript of the judgment. This document must then be filed with the County Clerk's Office (the "home" county clerk). After this is done, the income execution can be issued and it must reference that the transcript was in fact filed with the county clerk.
All executions (income or property) can only be issued (signed) by the clerk of the court where the judgment was entered, the county clerk of the home county, or a lawyer licensed to practice in NY State.
NOTE FOR JUDGMENT CREDITORS : You must indicate on the income execution forms the full name and address, including zip code, of the judgment debtor & employer. If the debtor is no longer employed by the named employer the income execution becomes ineffective & is returned to you. The Sheriff does not perform any searches or follow-ups with respect to the debtor's residence, place of employment and so on."
Source:
http://www.erie.gov/sheriff/civil_division_feeschedule.asp
Also, here is some information from the NY City Marshalls 'handbook':
http://www.nyc.gov/html/doi/html/mar5.html#3s
And here is a link to the NY Statute:
http://assembly.state.ny.us/leg/?cl=16&a=41