22 CFR § 906.8 - Witnesses.
(a) General. Each party shall be entitled to examine and cross-examine witnesses at the hearing or by deposition. A party wishing to take the deposition of a witness shall give the other parties reasonable notice of the time and place of the deposition and of the identity of the witness.
(b) Availability. Upon request of the Board or upon request of the grievant/charged employee deemed relevant and material by the Board, an Agency shall promptly make available at the hearing or by deposition any witness under its control, supervision or responsibility. If the Board determines that the actual presence of such witness at the hearing is required for just resolution of the case, the witness shall be made available at the hearing, with necessary costs and travel expenses paid by the Agency which is a party to the hearing.
(c) Notice. The parties are responsible for notifying their witnesses and for arranging for their appearance at the time and place set for the hearing. The Board may preclude a witness from testifying because of the failure of the party responsible for witness' appearance to comply with this section.