Act Governing the Employment of Diplomatic and Consular Personnel Stationed Overseas Article 8

Diplomatic and consular personnel stationed overseas who perform the same function for a six-year term and do not receive a Grade A performance evaluation in any year shall no longer be dispatched overseas.
中文原文 駐外外交領事人員任用條例第8條
駐外外交領事人員,如任同一職務滿六年,歷年年終考績(成)無一年列甲等者,不得再任駐外職務。

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