Dantès was now thirty-three years old, as we have said, and his fourteen years in prison had brought what might be described as a great spiritual change to his features. He had entered the Château d'If with the round, full, radiant face of a contented young man whose first steps in life have been easy and who looks to the future as a natural extension of the past All that had changed utterly. […]
Edmond smiled when he saw himself. It would have been impossible for his best friend—if he had any friends left—to recognize him; he didn't recognize himself. (22.9, 11)
Here we see a "spiritual change" made manifest via a physical transformation.
"The time when there were two nations in France has passed. The leading families of the monarchy have melted into the families of the empire and the aristocracy of the lance has married the nobility of the cannon." (51.36)
It needs to be remembered that, even as Edmond's life is being transformed, so too is the entire country of France.
"Like the Sleeping Beauty's castle, the whole house had been awakened from its long sleep and come to life; it sang and blossomed like one of those houses that we have long cherished and in which, when we are unfortunate enough to leave them, we involuntarily relinquish a part of our souls." (62.5)
Some of the Count's transformations are entirely superficial and, it seems, totally positive. In this case, the pleasant new exterior masks a dark secret.
With a black satin collar fresh from the tailor's hands, a newly trimmed beard, grey moustaches, a confident eye and a major's uniform with three medals and five ribbons—in short, an impeccable veteran's costume: enter Major Bartolomeo Cavalcanti, the loving father we met a short while ago.
Beside him, in a brand-new outfit and with a smile on his face, walked Andrea Cavalcanti, that obedient son whom we also know. (62.56-57)
Apparently, all it takes to turn a lout and a criminal into a respectable family is a couple of new outfits.
Edmond Dantès, the Count of Monte Cristo
A moment later, the door through which the priest had entered opened and Monte Cristo appeared. "Forgive me, dear Baron," he said, "but one of my good friends, Abbé Busoni, whom you saw enter, has just arrived in Paris. It is a long time since we last met and I could not tear myself away from him immediately. I hope that this reason will be sufficient to persuade you to excuse me for keeping you waiting." (66.6)
The facility with which the Count can change his appearance and behavior is amazing, at times comically so.
On his departure, M. Andrea had inherited all the papers affirming that he had the honour to be the son of the Marquis Bartolomeo and the Marchioness Leonora Corsinari. He was thus more or less established in Parisian society, which is so open to receiving strangers and treating them, not as what they are, but as what they wish to be. (76.2)
Making a change and starting afresh is easy – when everyone around you has probably already been through the process, and expects you to do the same.
"I know you, Albert. Whatever path you follow, you will soon make this name illustrious in it. So, my friend, come back in the world, made still more brilliant by your past misfortunes; and if that is not to be, despite all my expectations, at least leave me that hope." (91.45)
Having already weathered a huge change in circumstances – two if you count her rise to wealth – Mercédès is certain that her son can adapt to his new reality, and there's nothing to suggest that he can't. If there's anything we, as readers, can expect, it's instability, the chance for change.
Edmond Dantès, the Count of Monte Cristo
"For in spite of all my woes, in spite of all my tortures, I can now show you a face rejuvenated by the joy of revenge, a face that you must have seen often in your dreams since your marriage…your marriage to my fiancée, Mercédès!" (92.105)
Here, the most powerful transformation is actually a return to the original state, a regression.
"My God!" said Morrel. "You terrify me, Count, with your lack of emotion. Have you some remedy for death? Are you more than a man? Are you an angel? A god?" And the young man, who had never flinched from any danger, shrank away from Monte Cristo, seized with unspeakable terror. (94.87)
Monte Cristo's ability to change makes him seem something more than human. If he can be more than one thing, it follows that he can be anything at all.
Danglars nodded to show he was satisfied. In the eyes of the world, and even in those of his servants, Danglars played the indulgent father and good-natured fellow; this was one side of the part he had chosen for himself in the popular comedy he was playing: an appearance he had taken on, which seemed to suit him as it suited the right profile of one of those masks worn by the fathers of the theatre in Antiquity to have the lips turned upwards and smiling, while on the left side the lips were turned down and sorrowful. We might add that, in his family circle, the smiling, up-turned lips dropped and become down-turned and dismal ones, so that most of the time the good-natured fellow vanished, giving way to a brutal husband and tyrannical father. (95.9)
Here's a more common kind of transformation. In the same way as you might have an indoor voice and an outdoor voice, Danglars essentially has an indoor personality and an outdoor personality.