Referendum Act Article 11

With the consent of at least one-half of the total number of proposers, the lead proposer may file a written application to withdraw a referendum proposal before the competent authority issues a notice for joint signature collection.
中文原文 公民投票法第11條
公民投票案於主管機關通知連署前,得經提案人總數二分之一以上同意,由提案人之領銜人以書面撤回之。

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