"Play A Simple Melody" follows the same format.

Bing Crosby and his oldest son, Gary, recorded "Play a Simple Melody" and
"Sam's Song" on June 23, 1950. They were released on a single disk
as "Gary Crosby and Friend." The disk sold more than a million copies
and spent 19 weeks in the pop charts.
"Play a Simple Melody" peaked at No. 2 for two weeks, "Sam's Song" peaked at No. 3.


PLAY A SIMPLE MELODY
(Irving Berlin) (1914)
Sung by: Bing Crosby and son Gary

{Verse 1}
Won't you play a simple melody
Like my mother sang to me
One with a good old-fashioned harmony
Play a simple melody

{Verse 2}
Musical demon, set your honey a-dreamin', won't you play me some rag
Just change that classical nag to some sweet beautiful drag
If you will play from a copy of a tune that is choppy
You'll get all my applause And that is simply because
I wanna listen to rag

{Verse 3A}
Play for me
That good old-fashioned harmony
Oh, won't you play for me
A simple melody

{Verse 3B}
Play from a copy of a tune that is choppy
You'll get all of my applause because
I wanna rag it
Ragtime melody


Arrangement:

Verse 1
Verse 2
Verses 1 and 2 together
--- instrumental break ---
Verses 1 and 2 together
Verses 3A and 3B together


This song has 2-16 bar sections with very similar chord construction.
The melody change in the second section seems to suggest a change in rhythm
but it is 4/4 all the way through. Bing and Gary sang different verses
at the same time. One lyric site calls this Counterpoint.

An old waltz from the 1930's "Sometime" does something similar.
The melody is played through while a second part, which could be a
standalone melody by itself, is played at the same time.
My music calls this Obligato.