hi frds.. y the directors for same brand films r changing? for ex the five parts of harry potter films r handle by diff directors.. who deciding the names to direct..
A little common sense here. The original director may already be working on another film so would be unavailable. The original director may have got fed up of waiting for the studio execs to finalise the deal and get the actors and crew into place and decide they no longer want to do it or no longer have the time to do it. The original director is not asked back to the sequels. The original director has decided there isn't enough money on the table. The orginal director doesn't like the direction that the sequels are going in and decline to return, or some wranglings onset put them off from doing another movie or their favourite actor they like to work with isn't available. Hope this helps, there can be many many other reasons, but those are the ones from the top of my head