37 CFR §42.408

1. (a)An administrative patent judge institutes, and may as necessary reinstitute, the derivation proceeding on behalf of the Director.
2. (b)Additional derivation proceeding. The petitioner may suggest the addition of a patent or application to the derivation proceeding. The suggestion should make the showings required under § 42.405 and explain why the suggestion could not have been made in the original petition.