(a) Entire interest. An owner of the entire interest in an involved application or patent may act to the exclusion of the inventor (see §3.71 of this title).

(b) Part interest. An owner of a part interest in the subject patent may move to act to the exclusion of an inventor or a co-owner. The motion must show the inability or refusal of an inventor or co-owner to prosecute the proceeding or other cause why it is in the interests of justice to permit the owner of a part interest to act in the trial. In granting the motion, the Board may set conditions on the actions of the parties.