Her surname is "Davis" on the 1849 ship Hartley and "Reese" on the 1860 census, death certificate and Find A Grave website. She married Alfred Rees 14 August 1859 in Utah.
"My father and [his] five daughters remained there [St. Louis] until 1852 when we started on our journey West. We stayed at Council Bluffs ten weeks, then we continued the journey west and arrived in Salt Lake City on September 19, 1852. . . . I crossed the plains with my father and sisters by ox teams. We were with the 13th company under Captain Williams Morgan." (Emma David Rees)
This family is not listed on the company roster.