No, you cannot. You have to finish your dual degree in IITK if you want to finish in 5 years. But, if you want to do your M.Tech from another IIT, you need to take admission as a fresh M.Tech. and spend another 2 years as any other M.Tech. student. (There might be some concession in GATE requirements for IIT B.Tech. with a certain CGPA. You will have to research that.)
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