how to get my arrangement back?

[pdxdjazz]

the title on each chart is different. There's an added number or other information in the title that you can use to tell them apart.

Your app has two places to see song charts
Songs--your main library, holds every chart you have.
And
Playlists-- groups of charts from your library.

To replace a song in a playlist (song 1) with a different one from your library (song 2):
Add song 2 to the playlist
iOS
Edit playlist (at the top of the playlist)
Scroll down to song 2, touch and hold the lines to the right of the title = and drag title 2 up to beneath title 1
Touch the red ball beside beside title 1 or swipe across to remove it from the playlist.

Android
Touch/hold title 2 and drag it up to title 1. Release
Swipe title 1 to remove

Take care.
"Removing" (from the playlist) will keep title 1 in your library. "Move to trash" will delete it from your device and from any other playlists it may be in.
)BOB