Complex sentence: Thinking that the film had been cancelled, Kamal Amrohi, one of the scriptwriters who was also a director, had planned to make a film on the same subject, but after Asif confronted him about it, Amrohi agreed to shelve his project.
Split into simpler sentences: Thinking that the film had been cancelled, Kamal Amrohi, one of the scriptwriters who was also a director, had planned to make a film on the same subject. However, after Asif confronted him about it, Amrohi agreed to shelve his project.