Personal Data Protection Act Article 35

If a data subject withdraws his/her delegation of the litigation rights in accordance with paragraph 1 of the preceding article, the part of the court proceedings relating to such data subject shall automatically be suspended, and such data subject shall make a declaration to become a party to the suit. The court may also, on its own initiative, order such data subject to become a party to the suit.After the incorporated foundation or the incorporated charity files a lawsuit with the court in accordance with the preceding article, if the withdrawal of litigation rights by some data subjects causes the number of remaining data subjects in the lawsuit to drop to less than 20, the court proceedings for the remaining data subjects may still continue.
中文原文 個人資料保護法第35條
當事人依前條第一項規定撤回訴訟實施權之授與者,該部分訴訟程序當然停止,該當事人應即聲明承受訴訟,法院亦得依職權命該當事人承受訴訟。
財團法人或公益社團法人依前條規定起訴後,因部分當事人撤回訴訟實施權之授與,致其餘部分不足二十人者,仍得就其餘部分繼續進行訴訟。

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