Civil Associations Act Article 42

Where a member (member representative) of a social association cannot attend a meeting of the members’ (member representatives’) assembly, he may entrust in writing another member (member representative) to represent him; each member (member representative) may restrict the agent to one.
中文原文 人民團體法第42條
社會團體會員(會員代表)不能親自出席會員(會員代表)大會時,得以書面委託其他會員(會員代表)代理,每一會員(會員代表)以代理一人為限。

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