Try
WWW.Gunsmiths.com & search for pistolsmiths near your zip code. It is a fairly easy job, unless the Serial # is stamped in a place that may require it's removal & re-stamping (I had this happen once). Also, note that while removal & re-stamping a Serial # maybe permitted by the BATFE (If done to their specs), it may not be legal in your state. It is not just firearms laws that impact this as some Consumer Protection Laws make it a crime to remove any manufacturer's original markings.