22 CFR § 92.60 - Examination procedures.
(a) Explaining interrogatory to witness. If the witness does not understand what an interrogatory means, the notarizing officer should explain it to him, if possible, but only so as to get an answer strictly responsive to the interrogatory.
(b) Refreshing memory by reference to written records. A witness may be permitted to refresh his memory by referring to notes, papers or other documents. The notarizing officer should have such occurrence noted in the record of the testimony together with a statement of his opinion as to whether the witness was using the notes, papers or other documents to refresh his memory or for the sake of testifying to matters not then of his personal knowledge.
(c) Conferring with counsel. When the witness confers with counsel before answering any interrogatory, the notarizing officer should have that fact noted in the record of the testimony.
(d) Examining witness as to personal knowledge. The notarizing officer may at any time during the examination of a witness propound such inquiries as may be necessary to satisfy himself whether the witness is testifying from his personal knowledge of the subject matter of the examination.
(e) Witness not to leave officer's presence. The notarizing officer should request the witness not to leave his presence during the examination, except during the recesses for meals, rest, etc., authorized in § 92.56 (g). Failure of the witness to comply with this request must be noted in the record.