Complex sentence: The role of the Inspector Satyaki "Rana" Sinha was first offered to Chandan Roy Sanyal, but he could not take the part due to other commitments; thus Parambrata Chatterjee, an actor of Bengali cinema, was chosen to play the role.
Split into simpler sentences: The role of the Inspector Satyaki "Rana" Sinha was first offered to Chandan Roy Sanyal but he could not take the part due to other commitments. So Parambrata Chatterjee, an actor of Bengali cinema, was chosen to play the role.