Instrumental Duet Flute,Instrumental Duet,Trombone - Level 3 - Digital Download SKU: A0.783687 Composed by Irving Berlin. Arranged by John Groves. Christmas,Contemporary,Film/TV,Holiday. Score and parts. 3 pages. John Groves #6558659. Published by John Groves (A0.783687). Happy Holiday - Flute & Trombone DuetTrombone part works as an optional Euphonium / Baritone B.C., Bassoon, Cello, anything in bass clef C instruments.Score Only.