An example of creative copying by Robert Burns (1759-1796)

Here is "The Plowman" from David Herd, Ancient and Modern Scottish Songs Heroic Ballads etc. in two volumes (1776), compared to Robert Burns's (1759-1796) re-working of the same lyric (or some closely related version).
 

Burns's use of the earlier text is not simply a case of adding new verses. Burns has both deleted and added verses. The verses he retained from the original he re-worded. The original's two choruses (shown in italics), Burns combined into a single composite chorus.
 
 

 

 

The Plowman
Herd(1776), Vol. 2, p. 144

The plowman he's a bonny lad,
and a' his wark's at leisure,
and when that he comes hame at ev'n,
he kisses me wi' pleasure

Up wi't now, my plowman lad,
Up wi't now my plowman;
of a' the lads that I do see,
commend me to the plowman.

Now the blooming spring comes on,
he takes his yoking early,
and whistling o'er the furrow'd land,
he goes to fallow clearly;

Whan my plowman comes hame at ev'n,
he's often wet and weary;
cast off the wet, put on the dry,
and gae to bed, my deary

I will wash my plowman's hose
and I will wash his o'erlay,
and I will make my plowman's bed
and cheer him late and early.

Merry butt, and merry ben
merry is my plowman;
of a' the trades that I do ken,
commend me to the plowman.

plow you hill, and plow you dale
plow you faugh and fallow,
who winna drink the plowman's health,
is but a dirty fellow. 

  The Plowman, by Robert Burns
Scots Musical Museum, (1788), #165.

The plowman he's a bonie lad,
his mind is ever true, jo,
his garters knit below his knee,
his bonnet it is blue, jo.

Then up wi't a', my plowman lad,
and hey, my merry plowman;
of a' the trades that I do ken,
commend me to the plowman.

My plowman he comes hame at e'en,
he's aften wat and weary;
cast off the wat, put on the dry,
and gae to bed, my Dearie!

I will wash my plowman's hose,
and I will dress his o'erlay;
I will mak my plowman's bed,
and cheer him late and early.

I hae been east, I hae been west,
I hae been at Saint Johnston,
the boniest sight that e'er I saw
was the plowman laddie dancin.

Snaw-white stockins on his legs,
and siller buckles glancin';
a gude blue bonnet on his head,
and O, but he was handsome!

Commend me to the barn-yard,
and the corn-mou',man;
I never gat my coggie fou
till I met wi' the plowman.