Regulations for the Private Viewing of Artifacts in the Collection of the National Palace Museum Article 6

If a private viewing date and time has been scheduled, the NPM reserves the right to reschedule if necessary, though the NPM shall give the applicant prior notice and arrange for another time. If the applicant cannot meet on the originally scheduled date, notice must be given a day in advance to reschedule, or else the viewing opportunity will be forfeited.
中文原文 國立故宮博物院接待特別觀賞研究提取庫藏古文物及藝術品辦法第6條
觀賞研究時間經主管單位排定後,本院如有特別原因必須更改者,得事先通知申請者另訂日期。
如申請者有特殊事故無法如期來院觀賞時,亦須先一日通知本院洽商改期,否則以放棄論。

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