At any time before the matter is submitted for decision the Board or hearing examiner may file or permit the filing of an amended or supplemental accusation. All parties shall be notified thereof. If the amended or supplemental accusation presents new charges the Board shall afford respondent a reasonable opportunity to prepare a defense thereto. Any new charges shall be deemed controverted, and any objections to the amended or supplemental accusation may be made orally and shall be noted in the record.