An intereresting case in point is the opening chorus of the musical "Showboat". This contains the line "N*****s all work on the Mississippi", which was apparently included by Oscar Hammerstein because at the time it was a slightly tongue in cheek self deprecating term used by the black community itself. There was never any suggestion of OH being a racist.

This subsequently was altered to:-

"Darkies work...

then to

"Coloured folks work...

then to

"We all work.....

Until finally no one at all worked on the Mississipi and the opening chorus was omitted completely.