\version "2.13.24"
\header {
composer = "Composer"
}
\header {
piece = "Piece"
}
\header {
title = "Piece"
}
\score {
\new Staff { c'4 }
\header {
piece = "New piece"
}
% overwrite previous one
}

\header {
composer = "Composer"
}
\header {
piece = "Piece"
}
\header {
title = "Piece"
}
\score {
\new Staff { c'4 }
\header {
piece = "New piece"
}
% overwrite previous one
}