(a) Filing and service. A party shall file the amendment with the administrative law judge and shall serve a copy of the amendment on all parties to the proceeding.

(b) Time. A party shall file an amendment to a complaint or an answer within the following:

(1) Not later than 15 days before the scheduled date of a hearing, a party may amend a complaint or an answer without the consent of the administrative law judge.

(2) Less than 15 days before the scheduled date of a hearing, the administrative law judge may allow amendment of a complaint or an answer only for good cause shown in a motion to amend.

(c) Responses. The administrative law judge shall allow a reasonable time, but not more than 20 days from the date of filing, for other parties to respond if an amendment to a complaint, answer, or other pleading has been filed with the administrative law judge.