(a) All documents required to be served under this part must be served personally, by first class United States mail, or by verified email address, except as otherwise provided.(b) Service upon a person's duly authorized representative constitutes service upon that person.(c) Official United States Postal Service receipts from certified mailing and email delivery receipts constitute evidence of service.(d) The OHA may, at its discretion, allow for alternate forms of service when it determines that such would be advisable.