On October 19, 2011, a USCIS Update was issued announcing processing improvements for certain naturalization and citizenship forms. USCIS had centralized intake of Forms N-336, N-600 and N-600K to the Phoenix Lockbox facility. The Dallas Lockbox facility now handles the Form N-300. This change streamlined the way forms are processed, accelerated the collection and deposit of fees and improved the consistency of our intake process.Please remember that impacted forms received at local and district offices after December 2, 2011, are no longer forwarded to the appropriate USCIS Lockbox facility. Beginning December 5, impacted forms that were received locally were returned to the individual with instructions on how to re-file at a designated USCIS Lockbox facility.