Administrative Litigation Act Article 290

Where the ruling which orders to conduct the retrial proceeding becomes binding, the original litigation proceeding shall be reinstated and be adjudicated in accordance with the applicable instances.The party initiating the motion for retrial shall automatically intervene in the litigation after the original litigation proceeding is reinstated.
中文原文 行政訴訟法第290條
開始重新審理之裁定確定後,應即回復原訴訟程序,依其審級更為審判。
聲請人於回復原訴訟程序後,當然參加訴訟。

English translation for reference only; the Chinese text prevails. Not legal advice.