The Copyright Amendment brought in a few important changes with respect to mode of assignment of works. Not exercising due care with these provisions might result in reversion of rights. Thankfully, some of these changes were all encompassing and not limited only to authors or owners of works for films.
Relevant provisions of Section 19 read as follows:
"19. Mode of assignment. ...
(4) Where the assignee does not exercise the rights assigned to him under any of the other…