Ibn 'Abbas said that Juwayriyya's name had been Barra and the Prophet, may Allah bless him and grant him peace, had renamed her Juwayriyya.  

أَنَّ اسْمَ جُوَيْرِيَةَ كَانَ بَرَّةَ فَسَمَّاهَا النَّبِيُّ ﷺ جُوَيْرِيَةَ  

Abu Hurayra said, "Maymuna's name was Barra and then the Prophet, may Allah bless him and grant him peace, renamed her Maymuna."  

عَنْ أَبِي هُرَيْرَةَ قَالَ كَانَ اسْمُ مَيْمُونَةَ بَرَّةَ فَسَمَّاهَا النَّبِيُّ ﷺ مَيْمُونَةَ