A Christmas Carol takes place in the year 1843 during Christmastime in London. Ebeneezer Scrooge feels it unneeded and unnecessary to celebrate. Even claiming it "robs him blind". Because of this attitude, people around him are negatively impacted and dislike the Scrooge.
Scrooge, one night while he is at home, is visited by the Ghost of Christmas Past, the Ghost of Christmas Present, and the Ghost of Christmas Future. Each of them take Scrooge to separate parts of his life.
The one that affected Scrooge the most was the Ghost of Christmas Future. It changed Scrooge into a changed man. Eventually, after being shown his grave and begging and pleading for change, he stated "Why am I being shown the future if it cannot be changed." Following that remark, the Ghost of Christmas Future crumbles to the ground most likely symbolizing a change in his future.
He does, in fact, change for the better. He corrects his wrongdoings and spreads Christmas cheer to anyone who would listen. He becomes nicer, and happier, and everyone around him could tell.