Regulations on Election and Recall in Civil Associations Article 17

When there are vacancies for directors and supervisors of civil associations, alternate directors and alternate supervisors shall fill the vacancies in due order. If the number of directors and supervisors still does not reach two-thirds of the number specified in the constitutions of civil associations, a by-election shall be held. When there are vacancies for the chairperson, standing directors or convener of the board of supervisors (standing supervisors) of civil associations, they shall be re-elected within one (1) month from the date of vacancy; however, if the term of office of the chairperson is about to expire within six (6) months, within one (1) month from the date of vacancy, the chairperson may be represented pursuant to the provisions of the constitutions of civil associations or one shall be elected by and from the elect directors, or directors if there no standing directors are set.
中文原文 人民團體選舉罷免辦法第17條
人民團體理事、監事出缺時,應以候補理事、候補監事依次遞補,經遞補後,如理事、監事人數未達章程所定名額三分之二時,應補選足額。
人民團體之理事長、常務理事或監事會召集人(常務監事)出缺時,應自出缺之日起一個月內補選之。
但理事長所遺任期不足六個月者,得自出缺之日起一個月內,依章程規定或由常務理事互推一人代理之,其未設常務理事者,由理事互推一人代理之。

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