Policy Memorandum: Representation and Appearances and Interview Techniques; Revisions to Adjudicator's Field Manual (AFM) Chapters 12 and 15; AFM Update AD11-42 [open pdf - 115KB]
"This policy memorandum (PM) provides guidance regarding representation and appearances and interview techniques in certain application and petition proceedings before USCIS [United States Citizenship and Immigration Services]."
Policy Memorandum: PM-602-0055.1
U.S. Citizenship and Immigration Services: http://www.uscis.gov/