How does Scrooge transform from Stave One to Stave Two?

In Stave One of A Christmas Carol, Scrooge is described as a "tight-fisted hand at the grindstone" and as "hard and sharp as flint." He does not donate money to charity, does not want to give Bob the day off nor spend Christmas Day with his only family, his nephew, Fred. In short, Scrooge is a mean-hearted and miserly man who shuns society and everybody in it. 

His meeting with the Ghost of Christmas...

In Stave One of A Christmas Carol, Scrooge is described as a "tight-fisted hand at the grindstone" and as "hard and sharp as flint." He does not donate money to charity, does not want to give Bob the day off nor spend Christmas Day with his only family, his nephew, Fred. In short, Scrooge is a mean-hearted and miserly man who shuns society and everybody in it. 

His meeting with the Ghost of Christmas Past, however, brings great changes to Scrooge. The ghost, for example, forces him to relive a number of experiences from his youth, including his lonely days at boarding school and the end of his engagement to Belle. Through these experiences, the reader begins to see rather dramatic changes to Scrooge. These changes begin very early in the stave, when Scrooge is shown a glimpse of his school days:

To hear Scrooge expending all the earnestness of his nature on such subjects, in a most extraordinary voice between laughing and crying; and to see his heightened and excited face; would have been a surprise to his business friends in the city, indeed.

Gone is the miserable and pessimistic Scrooge, replaced by happiness and nostalgia. This is  a turning point in Scrooge's life which is further reinforced by seeing his former fiancée, Belle. Seeing her prompts feelings of guilt and regret, as Scrooge recognises the effects of his actions on others. He can no longer bear to relive such memories:

"Remove me!'' Scrooge exclaimed, "I cannot bear it!"

By the end of Stave Two, then, Scrooge's place on the road to redemption is well-established. His character is beginning to experience a positive transformation and this will grow in strength over the next two visits.