(b) Cooperation. The purposes and policies of the Statute can best be achieved by the parties' full cooperation and their timely submission of all relevant information from all potential sources during the investigation. All persons must cooperate fully with the Regional Director in the investigation of charges. A failure to cooperate during the investigation of a charge may provide grounds to dismiss a charge for failure to produce evidence supporting the charge. Cooperation includes any of the following actions, when deemed appropriate by the Regional Director:

1. (1) Making union officials, employees, and agency supervisors and managers available to give sworn/affirmed testimony regarding matters under investigation;
2. (2) Producing documentary evidence pertinent to the matters under investigation;
3. (3) Providing statements of position on the matters under investigation; and
4. (4) Responding to an agent's communications during an investigation in a timely manner.

(c) Investigatory subpoenas. If a person fails to cooperate with the Regional Director in the investigation of a charge, the General Counsel, upon recommendation of a Regional Director, may decide in appropriate circumstances to issue a subpoena under 5 U.S.C. 7132 for the attendance and testimony of witnesses and the production of documentary or other evidence. However, no subpoena, which requires the disclosure of intramanagement guidance, advice, counsel, or training within an agency or between an agency and the Office of Personnel Management, will issue under this section.

1. (1) A subpoena can only be served by any individual who is at least 18 years old and who is not a party to the proceeding. The individual who served the subpoena must certify that he or she did so:

   1. (i) By delivering it to the witness in person;
   2. (ii) By registered or certified mail; or
   3. (iii) By delivering the subpoena to a responsible individual (named in the document certifying the delivery) at the residence or place of business (as appropriate) of the person for whom the subpoena was intended. The subpoena must show on its face the name and address of the Regional Director and the General Counsel.
2. (2) Any person served with a subpoena who does not intend to comply must, within 5 days after the date of service of the subpoena upon such person, petition in writing to revoke the subpoena. A copy of any petition to revoke must be served on the General Counsel.
3. (3) The General Counsel must revoke the subpoena if the witness or evidence, the production of which is required, is not material and relevant to the matters under investigation or in question in the proceedings, or the subpoena does not describe with sufficient particularity the evidence the production of which is required, or if for any other reason sufficient in law the subpoena is invalid. The General Counsel must state the procedural or other grounds for the ruling on the petition to revoke. The petition to revoke becomes part of the official record if there is a hearing under subpart C of this part.
4. (4) Upon the failure of any person to comply with a subpoena issued by the General Counsel, the General Counsel must determine whether to institute proceedings in the appropriate district court for the enforcement of the subpoena. Enforcement must not be sought if to do so would be inconsistent with law, including the Statute.