If your a new instructor taking over midway what are some good approaches to take.

students very upset over new instructor taking over, very disliking of teaching any way different from other instructor, any suggestions.

Being put in as a replacement instructor, on the last 3rd of their learning degree. They all exhibit some back behaviors, that other students in the other classes are not doing on this wide of a scale. My approaches are a little stricter/less laid back then prior instructor. How do I gain control coming in as a replacement this late in the game without rebellion.