-- Get the selected region
local region = finenv.Region()
-- Get the top and bottom staff
local topstaff = region.StartStaff
local bottomstaff = region.EndStaff
-- Make sure that the swap can take place
if topstaff < 1 then return end
if bottomstaff < 1 then return end
if topstaff == bottomstaff then return end

-- Create a top region
local topregion = finale.FCMusicRegion()
topregion:SetRegion(region)
topregion.EndStaff = topstaff

-- Create a bottom region
local bottomregion = finale.FCMusicRegion()
bottomregion:SetRegion(region)
bottomregion.StartStaff = bottomstaff

-- Copy the music to clip files
topregion:CopyMusic()
bottomregion:CopyMusic()

-- Paste top contents to the bottom staff
topregion.StartStaff = bottomstaff
topregion.EndStaff = bottomstaff
topregion:PasteMusic()

-- Paste bottom contents to the top staff
bottomregion.StartStaff = topstaff
bottomregion.EndStaff = topstaff
bottomregion:PasteMusic()

-- Release the clip files
topregion:ReleaseMusic()
bottomregion:ReleaseMusic()

-- Make sure the original region is visually restored
region:SetInDocument()