A solo
responsorial psalmody.
Responsorial
They would be called a soloist.
performance of music or dance especially by soloists called RECITAL
Burgundian
it was a soloist called lorde
The word could be a performance.(A recital is a musical performance by a soloist or two performers; a concert is a performance by a group.)
call and response
it was a soloist called lorde
A soloist.
I believe the answer you are looking for is concerto - a work for orchestra and soloist.