\version "2.18.0"

RH =
\relative c' {
  \clef treble
  \time 6/8
  \ottava #1
  a'''8 \change Staff = "down" f, r r4. |
}

LH =
\relative c' {
  \clef treble
  \time 6/8
  \ottava #1
  s2.
}

\score {
  \new PianoStaff <<
    \new Staff = "up" \RH
    \new Staff = "down" \LH
  >>
}