43 CFR §4.1305

1. (a)An individual filing a petition may amend it once as a matter of right before receipt by the individual of an answer, motion, or statement of OSM made in accordance with § 4.1304 of this part. Thereafter, a motion for leave to amend the petition shall be filed with the administrative law judge.
2. (b)OSM shall have 30 days from receipt of a petition amended as a matter of right to file an answer, motion, or statement in accordance with § 4.1304 of this part. If the administrative law judge grants a motion to amend a petition, the time for OSM to file an answer, motion, or statement shall be set forth in the order granting the motion to amend.