There are movies that were produced years ago and then revived again but with the twist. The original actors and actresses will no longer play their original roles. They would be replaced but others could be retained. A recast of a movie happens with various reasons. One is that the actor or actress do not want to perform the role again in the movie. With this, they have to find another actor or actress that would satisfy the requirements for the specific role.
When the actor or actress that originally played the role may not be traced back then they have to find a replacement. Or even if he or she is still in the industry but they are not fit already to the role. Then a replacement would be sought. Replacement could be also the reason because of the stunts that should be done but the old cast cannot do it. There are times when the original actor play again the role when movies are revived and it is accepted by the audience.
There is a danger or risk that comes with recasting in movies. Even if the director and producer thought that the new cast would do great, the audience may not accept it. There are already many movies that have been recast and many also have failed. The new actor or actress did not meet the requirement or did not get the charm of the audience. These movies could be recast again and a new actor or actress will play the role.