I love to read Mahaabhaarat. As it might be supernaturally correct and may be shockingly a fiction. But still I love to read it. Because there are so many good things to read in it, so many strange things to read in it, so many wonderful things to read in it and so on. A few examples are cited here where people have changed their role by changing their Varn. Although it is not good or strange or wondrous thing in this age, but still it is worth noticing and knowing. So let us start --
From Braahman to Kshatriya. Parashuraam Jee was the son of a Rishi named Jamadagni. Read the story of his birth here. He was there during the reign of Sahastrabaahu (or Kaartveerya Arjun). Once Sahastrabaahu happened to be in the Aashram of Jamadagni and was astonished to see the powers of his cow Nandinee. He asked him to give that cow to him, but Jamadagni did not give her to him. When he wanted to take her forcefully, she created an army from her body and pushed the King's army back. This filled his sons with rage, so they took the cow away and killed Jamadagni Jee. When Parashuraam Jee came home, he killed the King and his all sons except four. Then he waged the war against all Kshatriya and emptied Prithvi from Kshatriya 21 times.
Strangely enough the same Braahman warrior Parashuraam who emptied Prithvi from Kshatriya 21 times, admits his defeat at the hands of proper Kshatriya Raam and Bheeshm. He fought with Raam because he did not tolerate Kshatriya. For the same reason when he came in Seetaa's Swayamvar, all Kshatriya kings got frightened. Although he had heard that Vishnu had incarnated on Earth, he just wanted to test Raam. And for the same reason he did not fight with Him with weapons, he just handed over his bow to Him and said - "Show me if you can handle this bow." As Parashuraam Jee handed over his bow, it itself went in His hands and that satisfied him that Raam was really the incarnation of Vishnu.
He did fight with Bheeshm. Although Bheeshm did not have to marry Ambaa because everybody knew that he had taken the vow not to marry his whole life, still Ambaa wanted to marry him. But Parashuraam Jee was angry because Bheeshm did not obey his Guru, but then Parashuraam jee had to accept his defeat at the hands of his disciple - Bheeshm.
How Dronaachaarya got converted from Braahman to Kshatriya. Drone was the son of Rishi Bharadwaaj. After finishing his education he could not get any wok as a Guru to teach his disciples. He was married to Kripee (Kripaachaarya's twin sister). Then they had a son also - Ashwatthaamaa. He was so poor that he could not even arrange milk for his son. He got frustrated by his living style, so he tried to see his childhood friend King Drupad to get a cow for his son, but he clearly refused to accept him as a friend. This refusal sowed a seed of revenge in his heart and he started looking for the ways to defeat him.
He needed money also to take care of his family. Fortunately Parashuraam Jee was donating his all wealth, so he went with the idea that he would get some in alms, but when he reached there he told him that he had already donated his all wealth, and he had only some arms and military arts knowledge, if he wanted that he could give it to him happily. Drone got ready and he learnt many good things from him. Fortunately at the same time Bheeshm was looking for good Aachaarya to train Kaurav and Paandav. He chose him and appointed him as the Aachaarya of Kaurav and Paandav to tech them military arts. He was one of the best warriors of Kaurav army in MBH war.
Kripaachaarya was the son of Maharshi Sharadwaan from an Apsaraa. That is how he was a Braahman.Sharadwaan came to know that his son was growing in Hastinaapur, so he went there in disguise and trained him in all four types military arts. That is how a Braahman became a Kshatriya. For some time he taught weaponry to Kaurav and Paandav too.
From Braahman to Kshatriya. Being the son of a Braahman father Dronaachaarya he should be a Braahman, but since his father was teaching Kaurav and Paandav military arts at the time of his childhood, he also learnt the same from his father along with them. And thus he became Kshatriya by Karm. Over the years living with Kaurav, he became a good friend of Duryodhan. Like him he also developed a kind of hatred towards Paandav. Not after long MBH war broke. And as Drone, his father, fought from Kaurav's side, so he also fought from their side. He was immortal. Duryodhan counted on the following seven warriors - (1) Bheeshm - he had the boon of Ichchhaa Mrityu; (2) Ashwatthaamaa - he was immortal; (3) Drone - he had many Divine weapons; (4) Kripaa - he was immortal. Among others were Karn, Dushaasan and Jayadrath. That is how his role of Varn changed.
Vishwaamitra was a Kshatriya, a King. How he became a Braahman from a Kshatriya, it is an interesting story. His real name was Vishwarath. He was the son of King Gaadhi and Maamaa of Maharshi Jamadagni and thus he was related to Parashuraam also. Read the story of his birth here.
Once a long famine happened in his kingdom so he came out to see his people. On the way he happened to be in Vashishth Jee's Aashram. When he knew this that he was near Vashishth Jee's Aashram, he went to pay his respects to him. Vashishth Jee offered him his hospitality. Vishwarath thought that how this Braahman will entertain so large army of mine, so he politely refused, but Vashishth Jee insisted on his hospitality and he agreed.
Vashishth Jee had Kaamdhenu cow, so he requested her to entertain the King and his army. Vishwarath was surprised to see the cow's powers. He asked Vashishth Jee to give that cow to him, because he thought that this type of cow should be with a King, not with a Braahman, Vashishth Jee refused to give her to him because she fulfilled all the needs of thousands of Rishi living in his Aashram. Vishwarath got angry at this and he wanted to forcefully take her but the cow produced her army from her body and that army killed the King's army.
Vishwarath did penance to please Shiv and asked all kinds of weapons to give to him, which Shiv Jee gave to him. He came to Vashishth Jee again and used his weapons to fight with him but Vashishth Jee made his all weapons useless by his Dand (scepter). Vishwarath understood that Brahm Power is greatest of all, so he started doing penance again. He did penance for several thousands years and at last got the status of Brahmarshi. Since then he got the name of Vishwaamitra. That is how he became the Braahman from a Kshatriya.
From Kshatriya to Braahman. Braahman's characteristics are great knowledge, forgiveness, charity, compassion etc. Even being a Kshatriya, because of these qualities, he was like a Braahman. There are several incidents of his such qualities in MBH. Forgiving Duryodhan for the incident of poisoning Bheem and Laakshaa Griha incident, giving all chances to Duryodhan at the time of Dice game inspite of knowing that he was cheating, freeing Duryodhan from Gandharv Raaj are some of them.
He has compassion for others. When Paandav go to forest, hey are followed by thousands of Braahman and students. Just to feed them, as he considers feeding them his Dharm, he pleases Soorya Dev and gets an Akshaya Paatra to feed those Braahman who were dependent on him.
His knowledge is manifest when Bheem is caught by the King Naush (in the form of a python) and Nahush asks him some questions. He answered them and freed both, the King Nahush, as well as his brother Bheem. Another time his knowledge is manifest when his four brothers die at the shore of a lake where they went to bring some water to drink. They did not answer Yaksh's questions there, so the Yaksh killed all of them. Only Yudhishthir replied his questions and brought his brothers alive and was blessed with the boon of not being recognized in incognito period. All these qualities make him a Braahman.
From Kshatriya to Braahman. Bheeshm was also a Kshatriya. He was trained like a Kshatriya too. Although he fought several fights and nobody could defeat him, but by heart he was a Braahman. He taught his father's two sons - Chitraangad and Vichitraveerya, and then Vichitraveerya's three sons - Dhritraashtra, Paandu and Vidur. Later his delivered so many teachings to Paandav, including Krishn, when he was lying on the bed of arrows, and was waiting for Uttaraayan to die. He loved justice and never tolerated injustice. Whatever he had to tolerate in his life, he tolerated it because of his sincerity to the kingdom. He gave Vishnu Sahastra Naam to people.