The Enforcement Act of Act of Military Service System Article 53

Male transferred to Substitute Services in accordance with Articles 8 or Article 12 and having time spent in service, military service and Active Service shall reduce the period of Substitute Services. The male prescribed in the preceding paragraph shall be canceled the conscription and mobilization by the Ministry of National Defense subordinating responsible unit and be assigned by the Ministry of the Interior the date and site to register.
中文原文 兵役法施行法第53條
依第八條或第十二條規定轉服替代役者,其已受之入伍及軍事訓練或服現役之時間,得折算為應服替代役時間。
前項人員,由國防部所屬權責單位辦理解除徵、召集,並由內政部指定報到日時、地點徵集服勤。

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