Answer:

alternate

AnswerCrossword Clue
ALTERNATEHow to shake up Etna?
ALTERNATEBackup
ALTERNATETake turns
ALTERNATEDeputy
ALTERNATEVary by turns.
ALTERNATEReciprocal.
ALTERNATESubstitute
ALTERNATEKind of juror
ALTERNATEVice, so to speak
ALTERNATESub
ALTERNATEWhat black and white squares do on a chessboard
ALTERNATEChange neat arrangement every second (9)
ALTERNATEEvery second
ALTERNATEStand-in
ALTERNATEDo this, then that, then this again