Vehicle License Tax Act Article 15

When transferring ownership of the transportation equipment already licensed for use, the transfer of ownership shall be registered with the traffic management authority as stipulated.Following the transfer of ownership of the transportation equipment, if the nature of use changes from originally exempt from tax or subject to a lower tax rate to taxable status or a higher tax rate, the tax amount for the difference shall be calculated on a daily basis and paid by the new owner or user. Conversely, if the transportation equipment, originally taxable or subject to a higher tax rate, changes to exempt status or a lower tax rate, the tax amount for the difference shall be calculated on a daily basis and refunded by the tax authority. Failure to comply with the stipulated procedures for transfer of ownership and failure to pay the required taxes as stipulated shall be considered as a transfer of the license for another use.
中文原文 使用牌照稅法第15條
已領使用牌照之交通工具所有權轉讓時,應依照規定向交通管理機關辦理過戶登記。
交通工具過戶後之使用性質,原屬免稅或原納較低稅額變更為應稅或應納較高稅額者,應按日計算差額部分之稅額,由新所有人或使用人繳納之;原屬應稅或原納較高稅額變更為免稅或應納較低稅額者,應按日計算退還差額部分之稅額,由稽徵機關退還之。
不依規定辦理過戶登記且未依規定補繳稅款者,視為移用使用牌照。

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