Complex sentence: Bangaldesh did hand over the sovereignty of the larger South Berubari to India instantly in 1974; however, India refused to transfer the much smaller "Tin Bigha Corridor" to Bangladesh.
Split into simpler sentences: Bangaldesh did hand over the sovereignty of the larger South Berubari to India instantly in 1974. India, however, refused to transfer the much smaller Tin Bigha Corridor to Bangladesh.