Complex sentence: Rumors began to circulate in late 1966 that Motown intended to rename the group "Diana Ross & the Supremes", a change officially announced in early 1967, after a concert where they were billed as "The Supremes with Diana Ross".
Split into simpler sentences: Rumors began to circulate in late 1966 that Motown intended to rename the group by placing Ross name along side the groups. In early 1967 it was officially announced that the group was to be billed as "The Supremes with Diana Ross".