How can the Hui people be surnamed Liu?

Most of the Hui people's surnames are changed. For example, in the seventh year of Zhiyuan (1207), Tiemaichi's son called Du Tiemu Lu (word), and his mother's surname was Liu, so he was renamed Liu Hanqing. (See Dictionary of Ancient and Modern Names) In the Qing Dynasty, he returned to Mo Ye, Ibler. "It used to belong to the Ministry of Internal Affairs, and later it was naturalized in Fengcheng County (belonging to Liaoning Province) and changed its surname to Liu, becoming the ancestor of the Hui people named Liu in Fengcheng." In addition, Liu Haci Buhua, who was a political official in Xing Ping, Henan Province in the 17th year of Yuan Zheng Zhi (1357), was praised by Tai Buhua (Dabuhua), a Hui nationality, because of his status of "Haci Buhua" and "visiting Machi military household", although Yuan Shi said that he was "ahead of Jiangxi people". Liu, who doesn't spend money, either gives it or changes it. In addition, among the Hui people in Gansu, in order to avoid the massacre during Tongzhi period, some Hui people such as Ma and Bai changed their surnames to Liu. Hui nationality with Liu surname is also widely distributed in China.