Complex sentence: In 1954, his agent recommended that he change the band's name from the Jose Calderon Sextet to the Joe Cuba Sextet and the newly named Joe Cuba Sextet made their debut at the Stardust Ballroom.
Split into simpler sentences: In 1954, he contracted an agent who recommended that he change the band's name from the Jose Calderon Sextet to the Joe Cuba Sextet. The Joe Cuba Sextet made their debut at the Stardust Ballroom.