The petition site lists over 30 scenes that were either altered or excised from the finished version of the film, in addition to the ending being substantially different from that which was shown in 2012 test screenings of the picture.
The petition suggests that the studio is currently looking into the possibility of releasing the extended director’s cut of the film and encourages you to call the studio in addition to signing the petition to express your interest in seeing the original version of the film that screened for audiences prior to the theatrical release of the picture.
The 2013 remake of Carrie was supposed to be a closer adaptation of the Stephen King tome but the final cut of the film wound up being a lot closer to a frame for frame remake of the Brian De Palma adaptation than a faithful adaptation of the King classic.
The image below outlines several of the deleted or altered scenes that fans are petitioning to have included in the proposed extended director’s cut.